Useful, interesting and must-know articles about aquarium care

Why Do Aquarium Plants Die?

Filed under Aquarium Care, Plant Care by Aquarium Care

Why my aquarium plants are dying?

Freshwater aquariums have untold value as both a living, breathing ecosystem in your own home for educational purposes as well as a gorgeous home decor item for your pleasure. There are a vast array of decorations you can put in your aquarium ranging from store-bought ceramic statues to driftwood, but the favored addition for many are plants. Beginning aquarists frequently opt for plastic or silk aquarium plants because they have a beauty similar to nature and are presumably easier to take care of than live plants. However, many have found that hardy live aquarium plants rarely require more maintenance than fake plants, and they really aren’t that difficult to keep.  Having trouble with plants dying and don’t know what’s causing it? There are a number of common, easy-to-fix causes of plant death.

By far the most common affliction for live plants in a freshwater aquarium is the light level. When selecting your plants, make sure that they all have similar lighting requirements, and that your aquarium can provide the ideal light level. In general, most low-light plants still grow in higher lighting — although many can grow out of control — so your best bet is to increase the lighting. If the style of your light fixture allows, this could be as easy as lining the bulb housing with aluminum foil to increase the amount of light reflected into the water.

The next concern is the nutrient level and water quality. Plants require nitrates as well as various trace nutrients in order to grow. They may also require CO2 injection into the tank, especially if your aquarium is well-aerated and has quite a bit of surface agitation as this will help the CO2 gas off quickly. Poor water quality (in general) can have a detrimental effect on aquarium plants; if the water isn’t within healthy parameters for the fish living in the aquarium.  It’s not healthy for the plants either. Water quality can be ensured through regular water changes and/or with a high-quality water maintenance product such as EcoBio-Block. EcoBio-Block contains beneficial bacteria to break down ammonia and nitrites into plant-usable nitrates as well as essential trace minerals to ensure the water stays at an optimal level between water changes.

Medications may also be to blame for plant problems. Many aquatic treatments and medications are harmful to invertebrates such as shrimp and snails as well as any live plants in the aquarium as they contain copper; these include any kind of algae destroyer as well as many ich medications, fungicide, and antibiotics. EcoBio-Block or a similar water maintenance product may reduce or eliminate the need for any of these treatments, as high water quality is critical for healthy fish. However, if you must use medications to treat the water, EcoBio-Block should be removed during the process as the live bacteria could also be harmed.

There is a lot that can be learned about what conditions might be ailing a particular plant by the color and pattern of blemishes and the way in which it dies that can help diagnose the issue; however, in the majority of cases the problem is one of the above which can easily be corrected.

2.

Nowadays many aquarists have decided to take a slightly different route with their tanks, rather than just use the tank to keep fish in with a few ornaments dotted about and the odd plant stuck in the corner, they are getting into the world of dedicating their tanks to a display of foliage where the plants are the main feature and any fish added are placed there for movement, taking second place to the greenery behind them.

Some keepers seem a bit daunted by this idea and are very reserved about taking the plunge but once this side hobby is taken on it is very rewarding and not as difficult to keep the plants healthy as many people think. More than often the hardest part is keeping the plants trimmed back when they are established, if this is not done on a regular basis, the tank will soon transform into a jungle unless slow growing species are specifically chosen. If you have decided to set up a planted tank then hopefully reading through this article will answer many of the questions you have yet to answer.

Starting off with a planted tank

The first thing to get right with your planted tank is the substrate that you are going to use, getting this right will ensure that the plants you add will be able to feed off the nutrients required to keep them healthy and have a good growth. Just adding plain gravel or sand may work in some tanks but eventually the food supply will run out and the plants will not be able to sustain the appropriate level of nutrients that they need, nowadays it is common practice to add a layer of specialised substrate below the gravel to act as a food source. There are many available to purchase from aquatic stores, some keepers will even add potting compost for this purpose, so do a little research and find out which is the best substrate for you.

Laterite is widely sold and is very good for this purpose but there are many more to choose from, many of the top companies like Tetra, JBL and Seachem produce purpose made media to use as the bottom substrate and are well worth looking at even though they may seem a bit pricey.

When your tank is cleaned and rinsed thoroughly add the plant substrate along the bottom of the tank to a depth of 2” (if using a larger tank the depth should be increased accordingly), this is your base layer, on top of this add another inch depth of fine gravel. The gravel that you decide to use is entirely your choice but I have always preferred to go for the 3mm fine gravel, this allows the roots to spread through quite quickly without them getting compacted. Sand is used by some planted tank keepers but this can clog the roots and I always try to avoid it.

Filtration for the tank is the next thing to be considered. You may be wondering why I didn’t mention this before we added the substrate to the tank, there is a reason for this. Some keepers are still using under gravel filters (UGF) in their tanks. This is not a god idea with a planted tank, in a short time the roots of the plants can easily clog up the plates on a UGF filter and render it useless, I would always suggest using a different method. Surprisingly the filtration in a planted tank tales a less important place in the table of musts than it does in a standard tropical fish tank. Because you are only going to add a few fish to the set up, less waste will be produced and if you get the balance right, the plants will convert the waste products to food for themselves, they definitely require some nitrates in the water so using a filter that is too efficient is actually detrimental to the health of the plants.

The main purposes of a filter in a planted tank are to remove any floating debris and keep your water clear, provide water circulation so that the nutrients and CO2 are spread evenly around the tank, and finally they will

act as a host for some of the CO2 units available to buy (this will be discussed in detail further in the article).

Any commercial filter rated for your tank is fine but do not use one that is over rated and definitely do not add any nitrate remover or similar media to it.

To your tank add several inches of water carefully; placing a saucer or something similar over the substrate will prevent it from being displaced as you pour the water in. Generally speaking the water needs to be harder rather than softer as this means that it should have a good supply of trace elements locked in it for the plants to feed on. Do not fill the tank at this stage as this will make the planting a difficult job, only adding a few inches will mean that you can access the substrate easier. Set the heater to the required temperature and once the water has heated planting can begin.

Adding your plants

It is always advisable to draw a rough sketch of how your final planting should look and this will give you a plan to refer to while you are doing the actual planting. When you have plants laid out in front of you it is quite easy to lose track of which plants you are planting in which position.

Basically there are three types of plants:-

Foreground plants - these tend to be the smaller species of plants that need to be at the front of the tank, they will spread, normally by runners and form a carpet of greenery.

Mid ground plants - As the name suggests, these are planted in the middle of the tank, in front of the foreground plants as they will grow slightly taller but not too tall.

Background plants - these are the tallest species of plants that need to go the rear of the tank, if placed at the front they would block out the view of the other plants that are in the tank.

There are many sites on the internet or books that will tell you exactly which plants you need as in their profiles the planting position will be added so that you can work out which plants are for the front or back of the tank.

There are several things to do before actually adding the plants to the tank.

Always inspect the plants for snails and rinse them off, remove any dead leaves or cut off any decay or browning, if left on it will start to poison the water as it rots.

When the plants have been removed from their protective packaging keep them moist, use a mister to keep giving them a spray every couple of minutes.

Add all of your plants in one go, do not add a couple of plants every week or so, all of the nutrients will be consumed by your plants but if there are not enough in there, algae will start to feed from the tank and over run your plants.

Use your finger or a pencil to create a depression in the substrate and carefully place your plant in there, cover over the roots with the substrate to anchor it down. Some cuttings etc. may refuse to stay down, in this case add a lead weight around the stem until the roots have established and then the weight can be

removed. If the plant is a rhizome plant do not bury the rhizome below the substrate but leave the top exposed. Bulbs should also be planted in this manner; this will prevent the top of the bulb from rotting.

Lighting for a planted aquarium

All planted tanks will need a lighting system that is capable of promoting growth in the plants. Different species of plants will require different lighting levels always check with your supplier as to how much light the plant actually needs.

As a general rule the lighting unit should be 2-3 watt of lighting per gallon of water. Therefore if your tank is 50 gallons you will need 100 watts of lighting. Fluorescent lighting systems are the most commonly used especially with the high output T5 tubes that are now available but if you are using a deep tank it may be necessary to upgrade to more powerful systems like Metal Halide or mercury vapour lamps. If you are adding plants that require different lighting levels it is not as problem, plants with low lighting requirements can simply be planted directly in front of species that require more light, this way they will get shaded as the plants grow.

Here are some examples of plants that require different lighting levels:-

Low lighting- Cryptocoryne, Vesicularia, Echinodorus

Medium lighting- Sagittaria, Aponogeton, Bacopa

High lighting- Cabomba, Lemma, Salvinia

Nutrients required by plants and adding them to the tank

As we have mentioned the plants will feed from nutrients in the water and from fish waste that has dispersed in the substrate but which nutrients are actually required. Below is a list of the required elements and what they actually do to benefit the plant.

Carbon - This is the main food source for the plants, it provides energy in the form of sugars that are created in the process of photosynthesis.

Nitrogen & Sulphur - These help in the process of protein synthesis where proteins are used for cell structural growth.

Phosphorous - This helps the plant in the development of flowers. Iron - This helps in the development of chloroplast where photosynthesis occurs.

Other elements are required in small amounts; if these are given in large amounts they can affect the health of the plant. They are as follows: - copper, magnesium, zinc, and calcium.

These will all aid in the plant growth but do not need to be added to the tank as they are natural trace elements in water.

Feeding the plants is usually done by adding liquid fertilisers or tablets that are placed in the substrate. There are many brands available to purchase but always follow the directions as if they are overdosed it can affect your plants and fish. Rather than adding one weekly dose I have found it far better to divide the total dosage into daily amounts, as this keeps the water more stable and the required elements will never deplete.

Photosynthesis & CO2 units

Photosynthesis is the process where the plants convert CO2 gas and water into glucose for cell structure and plant growth. In the daytime the plants will absorb the carbon from the CO2 gas and the by product of this is oxygen released onto the water which will be beneficial to the fish. At night time as the lighting ceases, so does the photosynthesis and the plants will start to take oxygen from the water and produce CO2. Because of this the pH of the water will rise at night as more CO2 is concentrated in the water but this should drop again in the daytime as the whole process starts again.

To help the photosynthesis occur more rapidly which in turn will make the plants grow quicker, many planted tank keepers will add CO2 artificially with units that are added to the tank. There are three main types of these available.

CO2 bio-systemsThese comprise of a container that holds varying amounts of yeast, sugar, and water. As the yeast ferments with the sugar, CO2 is produced and this is fed to the tank by means of tubing, the CO2 will then dissolve into the water. This is the cheapest option to use but it can be difficult to accurately see how much CO2 is being added to the tank.

CO2 mechanical systemThis is a much more reliable system, the amount of CO2 added to the water can be controlled better and it is much more efficient. It uses a bottle of CO2 gas that has a regulator fitted with a needle valve and a bubble counter, the CO2 enters the tank with tubing that has a diffuser on the end. The amount of gas being used is controlled with the needle valve and the bubble counter gives you a visual reading of bubbles per minute so that the water does not get too concentrated with CO2 causing problems with the pH. Most of these units will have a solenoid fitted so that they automatically switch off at night when the plants no longer need the CO2.

CO2 electrolysis systemThis is a high-tec unit that sends an electrical current into a carbon block causing it to release CO2 into the water. This unit can monitor its own output and the carbon block is easily replaced when it has been used.

With a planted tank the secret to running it successfully is to balance out the lighting and CO2 addition to get the most efficiency from the photosynthesis and to keep the nutrients in the water at a level where the plants have enough but not too much. One of the by products of getting this balance wrong is a mass onslaught of

algae in the tank.

Often with an outbreak of algae keepers will rush out and buy a cure off the shelf without realising that these additives will also affect the health of the plants. It is far better to decrease the nutrients going in to the water or reduce the lighting hours to starve the algae out of the tank. Algae can feed from water that contains no nutrients if it is attached to a leaf of a plant that is having die back and the leaves are turning brown. This is why it is important to keep removing any brown or decaying leaves.

Preventing disease and poor health in the plants

Just like fish, plants can contract diseases and die off very quickly but there are preventative measures to eliminate this problem as much as possible.

Never buy a plant that doesn’t look healthy. Sterilise your plants before adding them to the tank; this is easily done by dipping them in a solution of

potassium permanganate for 10-15 minutes. Inspect your plants and remove any brown or decaying leaves before planting. When healthy plants are

first introduced into the tank some leaves may die off; this is perfectly normal and the plants will recover.

There are other tell-tale signs that will tell you if your plants are not growing as they should be or are in poor health.

Slender stalks and leaves dying off at the bottom of the plant is a sure sign of insufficient lighting, either try extending the lighting hours or invest in an additional lighting unit.

Small brown spots or yellowing of the leaves will probably be due to the nitrates in the water being too high, increase the percentage of the water changes that are performed.

Stunted growth, this is usually a deficiency of CO2 in the water, this is overcome by increasing the bubble rate on the CO2 unit and decreasing the aeration of the water.

Small holes appearing in the leaves or on the edge of the leaves but the colour is still healthy looking, for this we can blame our little friends – the tank snails. The only way on ensuring that the snail population is kept to a minimum is to remove as many as you can see by hand and keep repeating the process.

Non-aquatic plants

Another common problem that a lot of keepers have is that there are a lot of non-aquatic plants being sold in the stores as suitable for aquariums. The sad result of this is that if they are added to the tank the end result will always be a dead plant that will decay and poison the water. The most common species that are definitely to be avoided are:-

Aglaonema Brazilian swords Dracaena Mondo Grass

These will not survive being submerged for more than a month even though they are quite common in the pet stores as suitable.

Pruning and propagating

Once the plants are growing nicely in the tank, they will need cutting back to keep the growth at a maximum. Plants like the Amazon Swords will at some stage need the outer leaves removing to let the inner leaves grow out and the taller plants will need cutting back as they reach the water surface. If done on a regular basis this is not a chore but seeing the plants looking nice and neat should give some self satisfaction.

It is possible to multiply your plant collection by propagating your present plants which in turn will save you the expense of purchasing new ones. There are 5 main groups of propagating methods depending on the species of plant.

CuttingsThese are taken from bunch plants and it is the easiest method of propagation. Simply put, a length of the plant is cut away and the bottom leaves of the cutting are removed, the bare stem is then placed into the substrate at about 1” deep, this will then root itself to create a new plant.

RunnersMany of the plants will send out runners across the substrate and new shoots will grow from these. Weighting the runners down on the substrate will allow the new shoots to develop roots and then the runner stem can be cut away.

RhizomeRhizome plants always produce side shoots and by dividing the rhizome into several pieces, a number of new plants will be formed.

Adventitious plantsThis is where young plants will grow out of the edges of the leaves of the mother plant. One well known species for this is Java Fern. Once the plantlets are large enough they will be released by the mother plant to settle elsewhere or they can be separated manually when large enough.

Seeds

Surprisingly many aquatic plants will produce flowers and propagate from seeds. A fine brush or a small paint brush is used to transfer the pollen to the different flower heads.

3.

Aquarium Plants

Aquatic plants perform a number of functions in the aquarium. They oxygenate the water and contribute to maintaining a balanced water chemistry. They serve as an additional site for colonisation by bacteria and may even help to seed new tanks with the beneficial bacteria required to break down waste products. However, plants are probably more often added because they enhance the look of the tank, while providing a refuge for fish. Well planted aquariums are a stunning site.

To grow plants successfully in the aquarium, you need to balance the amount of lighting with nutrient levels. Standard aquarium hoods often have only a single tube and this may not be adequate for most plants. If the light is increased, however, you may need to use a fertilizer or nutrient supplement and possibly CO2 addition to keep plant growth vigorous and avoid excessive algae.

It is unnecessary to leave lighting on for more than 12 hours a day - longer periods are likely to favour algal growth, rather than promote plant growth. Consider adding algae eating fish if appropriate to the setup, Otocinclus species are particularly suited to smaller planted tanks, as they will not damage leaves.

When planting a new tank, it is advisable to add all of the plants at the start, so that they become established before algae has a chance to utilise any excess light and nutrients. Include some quick growing plants in the initial stages. Floating plants are useful if you wish to shade part of the aquarium which will be left unplanted (or contain low-light plants), catfish and some others will appreciate an area away from the glare of the main lights.

Outlined below are a few basic plant care tips.

Before planting, remove any decaying or yellowed leaves. Decaying leaves are a drain on the plants nutrient supply.

Remove any dying roots, as these will rot in the substrate. These will appear limp and brown, healthy roots are normally pale and more rigid.

For stem plants, remove the bottom few leaves. These will receive little light and a new cutting will not have an adequate root system to support a full complement of leaves.

Tubers should be planted at an angle in the substrate, with the growing tip exposed. Some plants require attachment to rocks or bogwood to thrive, rather than planting in the substrate, these

include Java Fern and Java Moss. Cuttings can be made from stem plants once they reach the surface. These can be replanted in the substrate

and will soon grow a new root system. Many plants reproduce using runners. The new plants can be separated from the parent plant once they have

established themselves, when they reach about one-third of the size of the original plant.

4.

PLANT CARE

Live aquarium plants are a worthwhile addition to the fish tank. In a well planted tank, the fish have better colors, live a more natural life, and appear more comfortable than in an unplanted tank. Though they need more care than plastic replicas, live plants can be kept with few problems as long as there is plenty of light and no plant-eating or plant-destroying fish.

****************Photosynthesis****************

Photosynthesis is the process by which plants convert carbon dioxide gas and water are converted with the help of light energy into glucose (energy) and oxygen gas. This process can be expressed in the equation:

6CO2 + 6H2O + sunlight => C6H12O6 + 6O2

Thus in an aquarium during the day, plants use the carbon dioxide, produced by fish, and water to produce oxygen and energy. The oxygen is used by fish for respiration. At night, there is no sunlight or artificial for the plants to carry out photosynthesis, so the plants must rely on respiration to make energy. So, plants take in oxygen and produce carbon dioxide. Because of nighttime plant respiration, the carbon dioxide level in an aquarium rises at night, but once the light is turned on, the carbon dioxide levels drop due to plant photosynthesis.

***********Substrate***********

Follow the suggestions under "Gravel" in theaquarium section for gravel set-up. In most cases, plants do best in fine gravel with some sort of base fertilizer. Base fertilizer is not required, but is recommended. Iron rich clay fertilizers like laterite, and other fertilizers manufactured for aquatic plants are suitable.

**********Lighting**********

One of the most important ingredients to a successful plant aquarium is strong lighting. As a general rule, 2-3 watts per gallon is sufficient for a well-planted aquarium. Often light is measured on a scale of lux. The following table gives the light requirements in terms of lux for plants growing at different water levels:

Light

Type Lux Watt/G Examplessubdued 100-500 1-2 Cryptocoryne, Vesicularia dubyanamoderate 500-1000 2-2.5 Sagittaria, Echinodorusbright 1000-1500 2.5-3 Aponogeton, Bacopavery bright 1500+ 3+ Cabomba, Lemma, Salvinia

Fluorescent bulbs have proven to be the most practical bulb for lighting planted tanks. However, in tanks deeper than 20" (50 cm), most fluorescent bulbs are not strong enough to illuminate the tank sufficiently, so mercury vapor lamps can be used. For mercury vapor lamps, use about 6.25 watts per inch (2.5 cm) of

tank length.

Be aware that the intensity of fluorescent tubes decreases subtly, with time. Thus one tube should be replaced every six months.

*******Water*******

Most aquarium plants can be kept in water with a hardness from 4-12 dH, and a pH from 6.5-7.2. For specific species, see the individual descriptions. The water should be kept as clean and clear as possible because free debris can settle on plant leaves or cloud the water, interfering with light intensity. Very few aquatic plant species can survive in brackish water.

***********Nutrients***********

Plants require macro- and micro nutrients to grow. Macro nutrients are substances that are required in relatively large amounts such as nitrates, phosphates, and sulfates. These nutrients usually occur naturally in the aquarium from tap water and fish. When these levels rise to excessive amounts, an "algae bloom" can result. Nitrate levels rise due to their production by fish. Thus these macro nutrients need not be added to the aquarium.

Micro nutrients are elements that are required in trace amounts. Micro nutrients important to plants include copper, iron, manganese, boron, zinc, and calcium. These elements are needed in only the smallest amounts, and excess can prove harmful.

The following table reviews some of the major nutrients important to aquatic plant growth. (The macro nutrients are marked with an asterisk*)

Nutrient - Function

Carbon* - the basic block of carbohydrates, which plants use for energy Oxygen* - important in plant respiration at night Hydrogen - (in the form of water) is needed for nutrient transport, among other functions Nitrogen* - (usually in the form of ammonia or nitrate) necessary for protein synthesis Phosphorous* - promotes flower development Sulfur* - used in protein synthesis Iron - used in chloroplast formation (chloroplasts are the structure in which photosynthesis occurs.

When there is a deficiency of nutrients, the plants suffer. If the leaves yellow faster than usual, there could be a deficiency of nitrogen or sulfur. If the leaves yellow starting at the tips or the leafs seem especially brittle, an iron deficiency should be suspect. Evidence of an over fertilization of iron or a manganese, phosphorous, or potassium deficiency is yellow spots on the leaves.

************Fertilization************

Because macro nutrients are usually available naturally in tanks, an all-around plant fertilizer cannot be recommended for aquarium plants. Instead use preparations of "trace elements" which are specially prepared for aquatic plants and are widely available in pet stores. Never overdose with a fertilizer because plants and fish can be damaged. Do not purchase a fertilizer than includes phosphate or nitrate, because

horrible algae problems may arise. Fertilizers are commonly available in liquid and pelleted forms.

*************Carbon dioxide*************

Carbon dioxide is used by plants for photosynthesis and is a fundamental compound to the success of a planted aquarium. Carbon dioxide is present in aquariums as a byproduct of fish respiration and nitrification, and dissolved in the water from the atmosphere. Carbon dioxide levels should range from 5-15 Mg/l, once the level surpasses 20 Mg/l, fish may be harmed. Remember that aerating the water quickly causes carbon dioxide levels to decrease. If the tank is heavily planted and lightly stocked with fish, or if the water is hard, carbon dioxide fertilization may be necessary. However, carbon dioxide fertilization is usually not required for a beautifully planted aquarium. Carbon dioxide can be added to the fish tank using a carbon dioxide fertilizing system. Carbon dioxide fertilization is more popular outside the United States than it is within.

***********Filtration***********

Almost any filtration system (mentioned in theaquarium section) will work in a plant tank. The main requirements of the filtration system are: 1) that it does not create much water disturbance, because precious carbon dioxide will be lost; (2) that the filter remove floating particles that may block the lighting or settle on plant leaves; (3) and that the filter create some current to keep nutrients moving through the water and to prevent debris from settling on leaves.

Undergravel filters are not the best choice because the air bubbles create surface disturbance and the filter plate limits substrate size and composition.

*********Planting*********

Before planting the aquarium, make a rough sketch of how the tank should look. Include rocks and wood structures and plants so that there is a plan to follow.

Plants fall into different categories as to how tall they grow and their shape:

Foreground: Foreground plants are small, low growing species that often form carpet-like mattings by producing numerous runner plants. Foreground plants often inhabit shallow water and may require bright lighting. Plant foreground plants in front of middle ground and background plants.

Middle ground: Middle ground plants are medium sized species that can be used behind foreground plants, but in front of background plants. Middle ground plants can block unsightly stems of background plants.

Background: Background plants are usually tall and can be used to block out heaters, filters, hoses, and wires. Background plants are generally fast-growing species that require less light than foreground and middle ground species.

Bunch Plants: Bunch plants are usually middle ground or background species that look good in groups of several. Bunch plants are often easily propagated by cuttings.

Specimen Plants: Specimen plants are usually large, decorative species that are planted singly in the middle ground or background. Specimen plants are often used as a focal point and may be

highlighted with a spot-light.

Contrast Plants: Different-looking plants can be used as a contrast to the other plants in the tank. Red-leafed plants can be used as a color contrast to green plants, while plants with pointed leaves can be used as a shape contrast to those with large round leaves. When contrasting plants, place plants with similarities in color, size, or shape away from one another, while planting plants with differences closer together.

Floating Plants: Floating plants require plenty of light, but must protected from leaf burn by leaving distance between them and the bulb. Floating plants often propagate very quickly by division and in a short matter of time, take over and aquarium and block out light. Floating plants should be kept out of the light path of plants below that require a lot of light.

***********Propagation***********

Plants have several means of reproducing. Some species reproduce amazingly fast, taking over an entire tank in a matter of weeks, while others do not appear to propagate themselves at all.

Cuttings: Cuttings are the easiest way to propagate plants. Simple cut a lengthy (6-8") section of stalk from the plant and plant it in the gravel. Plant cuttings with at least 1" (2.5 cm) of the stem under the substrate. Remove the leaves on the section that will be in the substrate. Plant tubers and bulbs at a 45° angle in the substrate with the growing tip pointing out of the gravel. Both the cutting and the original plant should continue to grow. Most bunch plants can reproduce by cuttings.

Runners: Many aquarium plants, especially foreground and Sword plant species produce outgrowths known as runners. These new shoots are formed on stems and usually grow along the substrate or within the substrate. Plants that reproduce by runners (daughter plants), are often prolific.

Rhizome: The roots of some plants produce side-shoots. These plants can be propagated by cutting the rhizome into pieces. Be sure to include some leaves and some roots with the rhizome. Replant the cut sections along the surface of the substrate. These sections should root.

Adventitious plants: Adventitious plants are plantlets that arise from the mother plant. The mother plant produces a number of plantlets with drift free of the mother plant, and root on their own. Adventitious plants will either be released by the mother plant or can be cut when the plantlets reach a suitable size. Also referred to as "division."

Seeds: Plants that flower produce seeds only after pollination, in nature, usually be insects. In aquaria, use a fine brush to transfer pollen from the stamens to the stigmas.

*******Pruning*******

Like land plants, aquarium plants need to be pruned and thinned on a regular basis. Many of the taller, stalky species will actually grow out of the water if they are left unpruned. Other tall species will grow along the water surface and block out light to lower species if they are not trimmed. Prunings of many species, can be replanted. With leafy plants, like Swords, the large, outer leaves may need to be removed to make room for new growth. Plants with floating leaves like Nymphaea species, need to be cut back so that the light is not blocked from lower plants. Cut the upper leaves until only the lower leaves remain. When plant branches become dense, they should be thinned by removing some branches.

***************Plants to avoid***************

There are several plants sold as aquatic plants in pet stores that are not actually aquatic. These plants do not grow for long underwater and eventually end up polluting the tank when they die. Among some of the commonly available nonaquatic species are: Aglaonema, Brazilian Sword, Cherry Hedge, Draceana (Princess Pine), Green Hedge, Mondo Grass, and "palms."

*****Algae*****

Almost every aquarium is plagued at some point by an "algae bloom." "Algae blooms" can be fueled by excess light, especially sunlight, and excess nutrients, especially nitrate and phosphate buildup. Thus "algae blooms" can often be prevented by regular water changes and placing the tank away from direct sunlight. There are several types of algae common in the aquarium:

GREEN ALGAE

Green thread (filamentous) algae: Green thread algae forms long, green, filaments which often grow from plants. Thread algae needs abundant light to thrive. Thread algae can be damaging to the aquarium by taking important nutrients that aquarium plants require. Thread algae can be controlled by algae-eating fish or by manual removal.

Pelt algae: Pelt algae adheres to plant leaves by a single filament an reaches a length of 0.8" (2 cm). Pelt algae usually develop in water with a high nitrate content and can cause plant leaves to die. To eradicate pelt algae, remove the filaments manually, introduce algae-eaters (Flying Foxes) or snails (ramshorn). Regular water changes slow pelt algae growth.

Suspended algae: Suspended algae usually resembles green water and is comprised of Volvox. Suspended algae is most commonly introduced when pond foods are fed. Suspended algae can be removed by a series of large water changes, filtering with a diatom filter, or using UV light. Algicides can also be used to get rid of suspended algae.

Green spot algae: A small, dark green algae that forms small, round spots on the leaves of plants and the tank glass. This species thrives in poor and unstable water conditions. Algae eating fish and snails can rid the aquarium of green spot algae. The stabilization of water conditions helps slow green spot algae growth.

Green bunch algae: This algae forms bunches up to 1.2" (3 cm) long. Green algae is most prevalent in tanks with excessive lighting and fertilization. Green bunch algae can be removed by hand or algae eating fish.

BLUE-GREEN ALGAE

Blue-green algae: Blue-green algae form a layer that covers plants and gravel. Blue-green algae are fueled by excessive illumination and high nitrate and phosphate levels. Blue-green algae can produce toxins that are harmful to fish. Blue green-algae are often refused by algae-eating fish because of its bad taste. Apple snails can slow blue-green algae growth, but the best treatment is 5-7 days of total darkness combined with several large water changes.

RED ALGAE

Beard algae: Beard algae forms long (up to 6"-15 cm), black to dark green, branches that are introduced with new aquarium plants and are prominent with high nitrate levels and/or carbon dioxide deficiency. Beard algae firmly attaches to plant leaves, so manual removal is damaging to the plant. Algae-eating fish can eliminate beard algae as can carbon dioxide fertilization.

Black spot algae: Black spot algae form small, black spots on plant leaves. The cause of black algae is unclear, but excess nutrients (nitrate) and light help its spread. Control is very difficult, the best means to take is to remove affected leaves.

Black brush algae: Black brush algae forms dark, muddy-green bunches that adhere leaves, rocks, gravel, and wood. This red algae causes leaves to die off and thrives in acidic water with a high nutrient load. Short forms can be removed by algae-eating fish, but long forms are best combated by carbon dioxide fertilization.

DIATOMS

Diatoms: Diatoms develop in aquaria that are poorly illuminated, have a high load of nitrate and phosphate, and a pH above 7. Diatoms forms a brownish layer on plants, rocks, and glass and can be removed by snails and algae-eaters. Diatoms die off when water conditions improve and lighting intensity is increased.

*********Algicides*********

Algicides are chemicals that can be used to eliminate algal growth in the aquaria. Algicides work on a limited range of algae including filamentous, blue-green, and diatoms. If possible, seek non-chemical means to combat algae as many algicides do have side affects towards plants.

****************************Trouble-shooting with Plants****************************

Besides algal infestations, plants can suffer other ailments, especially when the water conditions are not favorable. Water with incorrect properties can cause as much or more damage to a plant than nutrient deficiency. If plants begin to wane (i.e. prematurely yellowing and losing leaves, leaf damage), first check that the water conditions are in order. If they are, see the chart below for help.

Symptoms Possible Cause Action-slender stalks-smaller leaves-lower leaves on plant stem-lower leaf loss

insufficient lighting Make sure that the plants have the right illumination period. Change the light bulbs if they have been used for longer than a year. Make sure that the lights are strong enough for the types of plants kept.

-small brown spots, developing into holes-yellowing leaves

high nitrate content from lack of water changes

Make a series of moderate water changes.

-small, irregular holes with sharp edges in otherwise seemingly healthy leaves

snail feeding Remove snails by hand.

-stunted growth-premature die off

carbon dioxide deficiency Start fertilizing with carbon fertilization. Decrease aeration.

*************************************Recommended Aquatic Plant Resources*************************************

Check out the following sites for quality information on aquarium plants:

http://www.csd.net/~cgadd/aqua/articles.htm http://www.aquabotanic.com/index2.cfm http://www.thekrib.com/Plants/ http://home.infinet.net/teban/ http://www.tropica.com/default.asp

5.

How to Grow Freshwater Aquarium Plants

Anubias nana with a small school of harlequin rasbora in the background.

Real plants do wonders for aquariums, providing fish with oxygen and even food. They keep the water chemistry more balanced, and provide scenery for you and hiding places for fish and other tank inhabitants. They're easy to care for, too.

Steps

1.

Left to right, java moss, java fern (back), anubias nana petite.

Select the plants you want to grow. It pays to do a bit of reading at this point, so check out aquarium forums and elsewhere. Consider the tank size, the scene you wish to produce and the size you want your plant(s) to be.

Remember, plants grow! Want something with lots of leaves, or more of a moss? How about something your fish will be able to eat?

o

These dwarf anubias won't grow much larger than a couple of inches tall.

You can find tiny, dwarf aquarium plants that grow only an inch or two tall, or obtain much larger plants for larger tanks.

2. Get a start of the plant(s) you want to grow. Either get an inexpensive, small start and wait for it to grow larger or purchase a more costly, larger plant. Plants are obtained at local pet shops, or other aquarists can provide you with starts. Either way, be careful of what you introduce to your tank. Plants can carry physical inhabitants from snails and shrimp to bacteria and diseases. Always look for a source that seems to practice good tank hygiene.

3.

Unwelcomed guests who slipped through...

Inspect the plant closely for snails and other visitors. Some of the tiniest water snails, no more than a couple of millimeters long, are rapid breeders. Unless you have loaches or other fish that will snack on them, they'll quickly take over your tank. You may quarantine a new plant outside your tank for a few days, to see if any snails appear.

4.

A small Amazon sword in a 10-gallon tank.

Most aquarium plants prefer to live entirely submerged, so don't let them dry out. If your tank is not quite ready or if you want to grow more of your plants than will fit in a tank, use a bucket or bin of water.

5.

Anchor the plants. Depending on the plant, this may be mostly an aesthetic matter, to keep them from bobbing around loose. For mosses, consider tying them loosely with string to a rock until they become established.

o In general, do not bury the rhizomes, which usually are thicker and greener than roots or stem, in gravel, as burying them can cause them to rot on many plants.

6.

Provide light. Aquarium plants, like any others, require light for photosynthesis. Check the light requirements of the plants you are choosing, many require high amounts of added light. Low light plants will do well if your tank has plenty of light from windows. Otherwise, plan to light your tank with a fluorescent full spectrum tank light.

• It's recommended that when you start out, stick to less than 2.5 fluorescent watts per gallon unless you put a carbon dioxide system in place. [1]

• "Cool White" or "Daylight" fluorescent bulbs are cheap, efficient, and effective enough for most purposes. [2]

7. Add fish. While not strictly required, fish waste will help to nourish the plants. The plants, in turn, will keep the water conditions better for the fish by absorbing carbon dioxide and releasing oxygen. Some plants are good at removing ammonia or nitrate. If you don't have fish already, wait a week after adding the plants before you introduce them to the lush environment you're creating.

8. Change the water periodically. Plants do not need water changes the same way that fish do, but it is still a good idea to change the plant water when changing your fish water. Do not siphon in your plant bed, as you may kill and injure them. Run your siphon over the top of the soil in which the plants are planted, and make sure you don't damage them.

9.

A red cherry shrimp, one of many creatures who will gladly eat your algae.

An otocinculus dwarf catfish, an eager algae eater for small tanks.

Remove algae. Algae growing on tank walls or on plant leaves competes with plants for light. You can remove algae manually by scrubbing or scraping the walls of your tank weekly when changing the water and rubbing the plant's leaves gently between your fingers. The far easier method, though, is to let your tank's inhabitants do the job for you. Shrimp and several catfish eagerly feed on algae and can help to keep your tank far cleaner with little or no effort on your part.

10.

An aquarium jungle

Divide or prune the plants if they outgrow your tank. Depending on your tank and your plants, you may find you have too much plant soon. Choosing slow-growing plants can help keep them small, but it can also mean having less plant and waiting longer for your plants to fill out. Find the right balance for your tank.

Tips

Aquarium plants come in all sorts of sizes and colors, so look around a bit before you choose. Have fun. This is an opportunity to enjoy some plants that air-breathers don't usually enjoy, and most aquarium

plants are easy to care for. If you do find snails, pick them off your plants and glass before they start breeding.

Warnings

Do not dispose of aquarium plants in local waterways. Many of them are non-native and do not belong there. Instead, if you have excess plants, let them dry out and dispose of them in the trash. Invasive aquatic plants reduce water quality impacting fisheries and recreational opportunities, costing millions of dollars.

Things You'll Need

A good light is a necessity. Substrates commonly used for aquatic plants include silt, sand, and clay. Peat needs to waterlogged and

covered. Layering is good technique. Heater - remember to adjust the temperature to one that your plants will benefit most from. A water pump is a good idea, as some plants benefit from circulation, but it is not compulsory.

Related wikiHows

How to Set up a Freshwater Aquarium How to Set up a Marine Reef Aquarium How to Make Your Fish Tank Look Professionally Designed How to Pick out the Right Decorations for Your Fish Tank How to Create Aquariums So Lizards and Fish Can Coexist

Sources and Citations

1. ↑ http://www.aquariumsecrets.com/Aquarium_Plants.htm2. ↑ http://www.aquariumsecrets.com/Aquarium_Plants.htm

Articles for You to Write

Here is a list of suggested articles that have not yet been written. You can help by researching and writing one of these articles.

How to Prune Plants How to Start a Freshwater Aquarium How to Grow Fish How to Grow Aquarium Plants How to Prune Aquarium Plants

6.

The key to a successful aquarium is to include the elements found in the fish's natural habitats. Aquarium plants are the most essential elements in aquarium. The plants add oxygen to the water, and absorb carbon dioxide, thus becoming another means of naturally regulating water chemistry to successfully house a community of fish.  Aquarium plants should be introduced in aquarium about a week before you acclimate starter fish.This article will simplify some of the key elements to a successfully planted aquarium.Lighting for aquarium plants.Sufficient lighting is very important for the success of a high growth tank. A recommended starting light level is 2 watts per gallon; note that these are florescent watts. There are a few aquarium plants that will survive and possibly even grow at lower light levels. Most freshwater fish tanks don't come with nearly enough light to grow plants. For example, the standard 55 gallon tank sold in the US comes with either one 40 watt bulb or two 15-18 watt bulbs. This is enough light to see the fish and prevent the majority of algae growth. Most any color temp or K bulb will work. Most people shoot for 5000k-6700k range. One thing to avoid is actinic reef lights. The blue light of these bulbs will not help aquarium plants much if at all and some people have said they tend to promote algae growth. One thing to note is if this is first foray into planted tanks you want to stay under 2.5 watts per gallon unless you are willing to invest the time and/or money into a CO2 system.Substrate for aquarium plants.Substrate is the secrets to growing beautiful aquarium plants without serious algae problem. Aquarium plants grow much better when they get their nutrients from substrate. Plants can receive nitrogen (N), phosphorus (P), sulpher (S) and several other trace nutrients (Fe, Bo, Mn, Cu, Zn, Mo) from substrate in the tank, which is absorbed by the roots. Retaining phosphate and iron sources in the substrate helps to limit availability of these nutrients to algae. Specialty substrates, such as Seachem Flourite, have high levels of iron or other needed nutrients. You can also use clay or soil containing substrate additives together with a small amount of organic material such as peat. The organic material provides nutrients for anaerobic bacteria to reduce insoluble iron (ferric) to soluble iron (ferrous). It also releases humic acids which are natural chelator chemicals which lock onto positively charged chemical ions like Fe++ and make it available in the water. These humic acids also help to buffer the pH in aquarium to a good value. The downside is that humic acids interfere with many test kits which measure CO2 and carbonate hardness.

It's not uncommon for planted tanks to have substrate in the 3-4" depth range. .

To enrich the substrate fertility for heavy feeders like sword plants or large crypts, prepare 1/2 inch clay balls with about 10 granules of 14-14-14 fertilizer. Dry these until hard and place 1 or 2 into the substrate near the roots of heavy feeders. Repeat as necessary if growth rates become low (about 6 months). It takes about 1/2 a teaspoon of clay to make a 10 mm (1/2") ball of clay. Each ball of clay will have about 70 mg of nitrogen which is the equivalent of 300 mg of nitrate and about 70 mg of phosphoric acid (P2O5). (Estimates based on 113 granules per teaspoon, a teaspoon weighs about 5.7 grams)A high quality iron test kit may also be useful. The peat and iron substrate can release enough iron to cause minor problems with algae for the first few months. That's why regular water changes are a good idea. Aquarium Plant Fertilizers.

You need to keep nutrient levels in balance to promote good plant growth and to keep algae to a minimum. To start off, it is best to use a commercial product like Seachem, which is time tested and widely available. Following are suggested nutrient levels:

Nitrates 5-10 ppm, Phosphates 0.5-1.0 ppm, Iron 0.1-0.3 ppm, and Potassium 10-20 ppm. If you water is very soft you may also have to provide a source of calcium and magnesium.

CO2.CO2 injection is VERY important for the success of a high light tank. if you want aquarium plants really actively growing with algae to a minimum, CO2 and stronger lighting is necessary to keep the balance between nutrients, light and CO2.. Use CO2 injection, either yeast method or compressed tank with regulator and micro-flow metering valve. Try to get 1 bubble per 4-6 seconds. The easiest way is to inject CO2 using a pressurized system.. For small tanks of size 27 gallons or less, it is suggested to aim for 1 bubble every 8 seconds. For larger tanks, 4-6 seconds per bubble is adequate. The pressurized system helps to introduce current into water which exercises the fish and greatly improves the rate of CO2 transfer to the aquarium plants. The ideal CO2 levels for a planted tank are in the 15-30 ppm range.

Water Chemistry for aquarium plants.

Drinkable tap water is fine to grow aquarium plants. Some plants may not do as well in extremely soft or hard water but most plants are very adaptable. A pH anywhere in the 6.4-8.5 range is good. A general hardness, gH, of 3-15 degrees and a carbonate hardness, kH, of 3-12 is fine. If water is very soft and you are using CO2 injection you want to be sure and add something to get kH up to at least 3 degrees to prevent large pH swings. If gH is very low then you may need to provide aquarium plants with calcium and magnesium.If you need to lower the pH then use CO2 injection. If you need to raise it then use something like baking soda or calcium carbonate. If you have questions ask.

Water changes.

Once you have a planted tank up and running and are adding fertilizers you should be doing regular water changes. A 50% water change every week is recommended. Smaller tanks require more frequent the water changes.Choosing aquarium plantschoice of aquarium plants for aquarium should reflect the area from which fish originate, as much as possible. Remember fish will be healthier the better you can simulate their natural environment.

DIY CO2

DIY CO2 PRIMER

Why DIY?

Pressurized CO2 systems are an expensive investment. You may not be sure it will be worthwhile, and would like to try CO2 injection to see how it affects plant growth before spending the money for a pressurized system. Or maybe you have 3 tanks in 3 different rooms, which would require 3 pressurized systems. Perhaps you are on a student budget and just can't afford a commercial system. Or maybe you have a 10 gallon tank and figure a full CO2 system would be overkill. 

For any of these reasons, a DIY CO2 setup would be worthwhile. It costs very little, can be set up in a single day, and only requires a few minutes of maintenance every few weeks. And the difference to your aquatic plants can be dramatic.

So How Does It Work?

A yeast culture is started in warm sugar-water inside a closed bottle with tubing leading into the

aquarium. As the yeast begins to reproduce and metabolize, it uses the sugar for energy and begins to produce CO2 as a byproduct. The CO2 builds up a slight pressure inside the bottle and then exits through the tubing into the aquarium. Various diffusers and reactors can be used to disperse the CO2 throughout the tank. The yeast culture continues to produce CO2 until all the sugar is used or until the alcohol level in the bottle reaches toxic levels.

How Do I Set Up a System?

You will need a 2L soda bottle or similar-sized glass or plastic container with a screw cap which fits tightly, some standard airline tubing, and silicone glue or Plumber's Goop from the hardware store.

Drill or punch a hole into the bottle cap to the approximate size of the airline tubing. You can use a 1/4" electric drill or a heated nail or any other way you can devise to put a hole in the cap. Insert the tubing so that it extends 1/4" to 1/2" into the bottle cap. Glue the tubing to the cap on both inside and outside. Allow to dry overnight. At some point on the tubing, insert a check valve so that gas can exit the bottle but not return. This will prevent any siphoning from the tank into the bottle.

RECIPE:  Using a funnel or rolled up paper, pour 2 cups of sugar into the bottle. Add 1/4 teaspoon of baker's yeast and a pinch of baking soda. Pour in a little warm water (NOT hot) and mix around to dissolve the sugar and yeast. Then fill to the shoulder (just above the label on a soda bottle) with warm water. Shake well and cap with the tubing-cap assembly. Run the other end of the tubing into the aquarium. 

This setup will serve an aquarium in the 10-30 gallon range.

To disperse the bubbles, you can do any of the following: 

- place the tubing into or under the intake to the canister, powerhead or power filter, allowing the filter impeller to disperse the bubbles. Caution - do not place the tubing in any high flow area which might create a vacuum in the tubing and collapse the culture bottle or siphon the culture into the tank!

- place an airstone on the end of the tubing and anchor in the aquarium.

- make a simple reactor. Plans can be found at http://www.thekrib.com/Plants/CO2/

Airstones and diffusion bells are less efficient than reactors and filter dispersal. 

I've Seen Other Recipes Out There - Why Should I Use This One?

You can use any recipe that works for you. The above recipe is a good one because it provides enough sugar to fuel the yeast for several weeks. In addition, it begins with a low population of yeast so that the culture will increase over a longer period of time and thus extend and modulate CO2 production. Adding more yeast will give a greater burst of initial CO2 output, but then the yeast will use up the sugar more quickly and die off more quickly. Using less sugar will decrease the overall lifespan of the culture. The baking soda helps to maintain pH and provide greater tolerance to the buildup of alcohol in the culture medium.

My Yeast Culture Isn't Producing Any CO2. Why?

Your yeast starter may be old. You can test its viability by adding a pinch of yeast to a little warm water. Wait 15 minutes or so. You should see some foaming on the water surface. If you don't, the yeast culture is too old and you will need to buy a new starter. Keep dry yeast in a closed container in the refrigerator when not in use.

You may have used overly-hot water to start the culture. Yeast likes very warm water but is killed by scalding water.

The room temperature may be too cold. Yeast growth will slow considerably in a cold room. If you cannot place the yeast bottle in a location which is warm (70 degrees F or more), you can keep the culture warm as follows. Place the bottle in a bucket. Add water to equal the level of liquid inside the bottle. Place a cheap aquarium heater ($7-10 from the department store) in the bucket and set it to maintain a comfortably warm temperature. This will keep your yeast growing at an even rate.

There may be a leak in the system. Check all connection points for leaks. Even a micro-leak can bleed out the CO2 before it reaches your aquarium. Use dishwashing liquid soap (you can cut it 1:1 with water if you wish, to spread thinner) smeared in a thin layer over all connection points to check for escaping air bubbles.

Be sure to minimize any water surface turbulence in the aquarium. Turbulence allows the CO2 you've injected to escape into the air. Minimizing turbulence will maximize CO2 levels in the water. 

My Aquarium is Smaller/Larger Than 10-30 Gallons. Can I Still Use DIY CO2?

Yes. For a smaller aquarium, scale back the recipe and bottle size accordingly. For a 5.5 gallon tank, you could use a 1/2L bottle and reduce the recipe by 1/4. 

For a larger aquarium (up to 50 gallons, at which point it may be worthwhile to invest in the pressurized system), several bottles can be combined into one system to produce sufficient CO2. Here is one method. Make 2 setups (2 bottles with drilled caps and airline tubing). Partway between bottle and tank, use a T-connector (found at the lfs - use a brass one to prevent cracking) to connect both lines from the bottles. From the T-connector, run a single line to the tank. This pools the amount of CO2 produced by both bottles, doubling the available amount. It is a good idea to place a check valve on each line entering the T-connector. This prevents back-siphoning, and allows you to change one bottle without losing CO2 from the other. Here is what one of my setups looks like (note the bucket and heater, as mentioned above, to maintain even temperature):

To maintain an even production of CO2, you can stagger the changing of these culture bottles - one every 2 weeks, or one every week, whatever you find to work for you.

Can I Add Anything to the Culture to Increase Production?

Some people have tried adding yeast nutrients or more sugar midway through the growth cycle. It is not a good idea to open the bottle once the yeast has begun to ferment!! The fermentation is an anaerobic process and opening the bottle will admit oxygen and stall the fermentation. The yeast will have to use up all the oxygen and then begin fermentation again. There is absolutely no reason to add anything more than is in the basic recipe. This should provide plenty of CO2. Addition of other nutrients at the beginning of the culture cycle can provide a growth medium for contaminating bacteria. This can have detrimental results for your tank. Sticking with the basic recipe and not interfering with the growth cycle will provide the best results.

What's This About Using Champagne Yeast?

"Champagne" and "Montrachet" yeasts can be purchased at brewing supply houses. These yeasts have a higher tolerance for alcohol and given enough sugar should be able to continue to ferment for longer than baker's yeast, perhaps as much as several months. If you want to experiment with these yeasts, check with your local brewing supplier, and try adding an extra cup or so of sugar to the water.

How Can I Be Sure My Tank pH Won't Crash?

It is most important to be certain that the aquarium water is well-buffered before adding CO2. The water should have a KH of 4 degrees or greater (or 70 ppm CaCO3, if that is how your test kit measures) in order to be able to maintain a stable pH with CO2 addition. A lower KH could lead to a situation where the buffer is exhausted and the pH suddenly crashes to 4 or less, with lethal results for your fish and plants. If your tank KH is not high enough, you can easily increase the buffering by adding some crushed coral (from the saltwater tank supplies at the lfs) in a filter bag in your filter. This will slowly dissolve, releasing calcium carbonate which will increase your KH. You will also see a rise in pH (the two parameters are chemically associated), but the CO2 will drop the pH back down again. You will have to use trial and error to determine the exact amount of crushed coral to use in the filter bag for your tank. Remember that after a large water change, the KH/pH can drop noticeably until the crushed coral dissolves into the new water

How Do I Know What Concentration of CO2 is in My Tank?

If you measure your pH and KH, you can correlate them to arrive at an accurate reading of CO2 levels. The correlation chart can be found at http://www.thekrib.com/Plants/CO2/kh-ph-co2-chart.html  , second chart on the page.

Is It Possible to Overdose With CO2? Will My Fish Suffocate?

It is not likely that you will overdose the tank with a DIY system. It just doesn't produce that much CO2. However, it is wise to monitor the pH and the reactions of the fish for the first few days. If the pH drops too low, you may not have enough buffering or you may be providing too much CO2 for the size of your tank. The plants should produce enough oxygen to provide plenty for your fish. However, if you should notice them gasping at the surface, particularly in the morning, the oxygen may have been depleted overnight and you will be wise to add an airstone at night to aerate the water. This is rarely necessary, but do monitor for it at first. Early morning is the best time to check for pH changes, as it will be at its lowest at this time. Note: CO2 does NOT displace O2 and cause suffocation. The two concentrations are independent of one another.

Will This Really Work?

You bet! There are some beautiful planted tanks out there which use only DIY CO2. It's inexpensive, easy to set up and easy to maintain. You are sure to be pleased by the results!

Written by Cathy Hartland

DIY Yeast-Generated CO2 System

By Hoa G. Nguyen

Carbon dioxide injection certainly is not necessary for all planted aquaria. You can have a beautiful planted aquarium without CO2, most likely if you limit yourself to a slow-growth setup, with less demanding plants and less fertilization. However, if you want to grow a wide variety of plants and have vigorous growth, you need higher light levels, adequate nutrients, and supplemental CO2.

Here is how a cheap Do-It-Yourself Yeast-Generated CO2 System can be constructed.

1. Drill a hole in the middle of the cap of a 2-liter softdrink bottle* slightly smaller than the diameter of a 3/16" air hose tube. Insert the tubing through the hole so that about 2 cm (or 1") is inside the bottle when re-capped. Cut the tube at a 45-degree angle (see picture) so that any water that gets onto the tube will drip back down more easily. Seal the insertion point with silicone caulk on both sides of the cap (the inside seal will be more important, due to the CO2 pressure which will be generated, so be generous with the caulk there).

2. Run the CO2 hose into the aquarium, through a one-way check valve, and terminating in an airstone in the aquarium. Leaving an air hose unattached at both ends, with one end in the aquarium, is an invitation to disaster. It is very easy for siphoning to start by accident. Capillary action draws aquarium water up the hose to the top of the tank, then an accidental yank on the hose can easily pull the hose out enough so that this water in the hose fall below the tank water level and thus starting a siphoning action. I had 20 gallons of water on my living room floor in a few hours, started in exactly this way. Therefore I strongly recommend having a one-way check valve in the CO2 path. Note that most cheap air-hose check valves do not last very long in a CO2 line. Carbonic acid formed by the interaction of CO2 with water tends to dissolve the rubber membrane. You should spend a few more dollars and buy a check valve made for CO2. By the way, NEVER put a shutoff valve (even under control of a solenoid or timer) in the CO2 line of a yeast-generated CO2 setup. If the line is shut, the pressure will keep building until the bottle bursts--very messy.

3. For the reactor, use a large-diameter plastic bottle (such as a Gatorade bottle). Cut out 3 large panels from the lower portion of the bottle. Insert the CO2 hose through a hole in one of the panes between 2 panels (see picture), near the bottom, and cap it with an airstone. Use stones to weigh the bottle down and place it in a rear corner of your aquarium. Place the water filter return spray bar vertically next to the bottle (secure to side of tank with suction cups). The idea is for the CO2 bubbles to come out of the airstone and collect at the top of the reactor bottle. The water from the spray bar then constantly agitates the CO2 surface and helps dissolve the CO2. The cap of the bottle allows it to be bled occasionally, to remove accumulated, undissolved gasses.

4. Now mix the yeast, sugar and water solution as follows.

* Put 1/4 to 1/2 teaspoon of yeast into the bottle with about a cup of warm water (bread yeast is fine). Some people have theorized that champaign or wine yeast should last longer (due to its ability to tolerate the alcohol generated from the brewing process), but recent tests reported on the net have not indicated any difference.

* Shake to mix the yeast well.**

* Add water to bring the solution up to 3/4 of the bottle.

* Add 1 to 2 cups of sugar and shake well. The amount of yeast and sugar will determine the rate and duration of CO2 generation. More yeast will result in stronger CO2 production, but will exhaust the sugar quicker. Using 1/4 teaspoon of yeast and 2 cups of sugar will result in CO2 production for about 4 to 5 weeks.

* In areas with soft water, some people recommend adding a teaspoon of baking soda to buffer the water and extend the life of the solution (prevent the acid formed by the brewing action from destroying the yeast prematurely).

The brew should generate about 1 bubble per second (from the air hose with no airstone), after about one day. Using warm water will help it get going faster. There is a ramping up period in the flow at the beginning and a ramping down period at the end of the solution's productive life. To smooth out the flow, you can use two smaller (1 liter) bottles, instead of one 2-liter bottle, and start one about a week or two after the other (but this doubles the maintenance effort). You should remove and clean the airstone occasionally, as yeast-generated CO2 has a tendency to generate a slime coating that gums up the airstone after a while.

Notes:

*

If instead of using the bell-type reactor described here, you choose to feed the CO2 line into a powerhead, as some people do, then you should consider using a more rigid bottle (e.g., juice bottles) than the standard softdrink bottles. The idea is to prevent to bottle from collapsing if there is a suction on the CO2 line (by the powerhead). This could push the yeast solution into your aquarium.

**

Occasionally you will read on the web or in the newsgroups that you shouldn't shake the bottle to mix the yeast with the water. This is a classic net.non-sense which started with a post in the rec.aquaria newsgroup a few years ago. One guy posted the instructions for a yeast-CO2 set up, and wrote, "Add the yeast to the water, but do not stir or shake the bottle. The instructions from my bread machine explicitly stated this." What he failed to understand was WHY his bread machine instruction was so. Anyone with a bread making machine could see this specific instruction, under the "Delayed Baking" mode. That's the mode where you put the ingredients into the machine, then set the timer and go to bed. Near morning, the machine will automatically turn on and start mixing, kneading and baking, and you will have fresh, hot bread as you get up in the morning. The instruction tells you to put in the water first, then gently put flour on top of the water, then put the yeast on the flour, and DO NOT MIX. That's because they don't want the yeast to get wet and get activated too early, resulting in bread that rises too much.

Anyway, this guy did not understand the reason for that instruction, but passed it on anyway. People read this guy's tip and started passing that piece of non-sense around. It made its way into archives, and occasionally pops up here and there. I always have a good laugh when I see it.

Since we want our sugar solution to start fermenting as soon as possible, please by all means, mix the yeast well. But don't shake the bottle after the cap with the CO2 hose has been screwed on. This might get some of the liquid into the line, which will be pushed into your aquarium once the CO2 starts producing.

DIY CO2 Injection: The Yeast Method

By Thomas Narten

INTRODUCTION

This article gives instructions for a cheap Do-It-Yourself CO2 injection system. The CO2 is produced by a mixture of sugar, yeast and water, and the setup is constructed entirely from cheap and readily available materials. Thanks go to Brian R Silverstein (silverst-at-armstrong.ecn.purdue.edu) for posting a description of his setup, which initially used sourdough starter. His message got me started and much of the information below comes from his postings. Not surprisingly, Brian thanks Ulli Kaeufl (hukaufl-at-eso.org) & George Booth (booth-at-hplvec.LVLD.HP.COM). Finally, a big thanks go to the many participants of the Usenet *.aquaria newsgroups, where this topic has been discussed many times, and numerous persons report positive results using this system.

Warning: This setup may not be suitable for everyone. It requires regular fiddling and the uncertain CO2 injection rate may lead to pH fluctuations that can kill fish (especially if you have soft water). My water is fairly hard (GH 140-180 ppm) and the pH varies from 7.8 with no CO2 to 7.0 with CO2. Read the FAQ on plants and CO2 injection before attempting this. CO2 is an important contributor to robust plant growth, but it is advisable to understand the big picture before going this route. It is particularly important to understand the relationship between pH, CO2 concentration and carbonate hardness. Note also that CO2 injection is a complete waste of time if one has inadequate light, as is typically the case with single-tube strip lights sold at most aquarium stores. One bulb usually produces an insufficient quantity of light, and typical bulbs do not produce the "full spectrum" of light plants require.

On the other hand, the described set up is an inexpensive way to observe first hand the benefits of CO2 injection on plant growth. I personally had never seen what CO2 could do for a tank before trying it myself, and would probably never have purchased a conventional CO2 injection system because of the high cost. In fact, I still haven't purchased one. I find the yeast method adequate for my current needs. I have been using it now for 8 months and have managed to acquire and successfully grow over 25 species of plants with only a handful of failures. Here are the steps.

CONSTRUCTING A CO2 GENERATOR

The first step is to create a CO2 generator. I use a 2-liter plastic soft-drink container. The "hard" part is attaching a hose to the container so that the CO2 doesn't leak out on its way to your aquarium. I use a number 3 rubber stopper with a 1/4 inch hole in the middle. A short segment of 1/4 inch copper tubing goes through the hole and connects to regular air hose tubing. I bought a stopper and copper tube from a campus chemical supply store for $ .45.

Note: Other folks have had success attaching the tube directly to the resealable cap. Simply poke or drill a hole through the cap, stick the tubing through it and seal it with the aquarium silicone sealer. The variations are endless.

BUILDING A CO2 REACTOR

The second step is to create a CO2 reactor for trapping and dissolving the CO2 bubbles before they escape to the surface of your aquarium. Note: For the first few weeks, I simply placed an airstone at the bottom of the tank and let the CO2 bubble to the surface. While inefficient, enough CO2 dissolved to make my plants grow noticably faster. Use of an airstone is suggested because the increased surface area of many small bubbles helps dissolve the CO2 faster.

More recently, I constructed a "sophisticated" reactor. The idea is to trap the rising CO2 bubbles before they reach the surface and escape. Doing so provides two benefits. First, less escaping CO2 means more CO2 in your tank. Second, the trapped CO2 bubbles act as a (very!) crude gauge of how much CO2 you have in your tank. If a lot of CO2 is trapped, the amount of dissolved CO2 in your tank is likely to be high. If little CO2 is trapped, your rig may not be producing CO2 at a high enough rate to replace that used by plants or escaping from your tank.

My reactor consists of a small clear plastic bowl that flower pots are placed on ($0.40 at any gardening store). I cut it in half, glued a clear piece of plastic to it and wedged it between the filter tube and aquarium glass just below one of the powerheads. The cutaway portion faces down creating a trap for rising CO2 bubbles. It is best to use clear plastic so that you can see how much CO2 is accumulating in the reactor.

Other folks have had success with a more sophisticated reactor that actually circulates water in the reactor in order to dissolve the CO2 faster. A nice reactor can be made from the wide end of a gravel cleaner. The 1/2 inch tubing attached to such cleaners connects directly to the exit of many powerheads. The reactor catches the CO2 bubbles, while the water from the powerhead churns and dissolves the CO2 and then flows into the tank.

Tetra also markets a "CO2 Bell", a simple reactor with suction cups that attach to the side of the tank. Since it is ready to go, it is the easiest to use, but finding them at local stores may be problematical, since few stores seem to market CO2 injection related products.

If you use a cannister filter, another possibility is to let the CO2 bubble into the filter intake. The CO2 will completely dissolve by the time it exits the filter. The "gravel cleaner" reactor described above can be used to catch the CO2 with the hose connecting it to the filter intake.

A SOURCE FOR CO2

The third step is to create CO2. I mix 3/4 cup sugar, 6 cups water and a pinch of yeast (roughly 1 teaspoon does the trick). The exact ratio of ingredients is not critical. For example, I use enough water to fill the bottle to about 3 inches from the top. You don't want to get the mixture too full, as the mixture may foam a bit, and you don't want the foam flowing into your tank.

Using the above mixture, I regularly get 10-14 days of strong CO2 production, at a rate of one bubble every 3-7 seconds. When the system stops bubbling (the drop in gas production is often precipitous), dump out everything and mix up a new concoction.

HINTS & DISCUSSION

1) I doesn't hurt to shake the mixture every 2-3 days. Early on it seemed to me that a mixture produced CO2 longer if I shook it every couple of days or so, but I am no longer sure that this is actually the case. (Note: it will be difficult to shake the mixture if it is too full!).

2) Hot water contracts when cooled. Actually, the hot air trapped in your rig contracts when cooled. If your mixture is warmer than room temperature, it may suck water out of your tank before it starts producing enough CO2 to reverse the flow. If your CO2 rig sits below your aquarium, bad things could happen.

One way to prevent problems is to insert a standard air valve between the mixture and the airstone. Right after mixing up a new batch, close the valve. Once the rig is producing CO2 again, open the valve.

Rather than bother with a valve, I simply keep a spare 2-liter bottle on hand. When the current batch looks like it's starting to peter out (or before, if you don't want to have your tank's pH go up as CO2 production wanes), mix up a new batch, but don't connect it right away. Let it sit in a corner for 12-24 hours and then hook up the new mixture when you know it's going strong. That way there is no interruption in CO2 flow through your tank.

Another possibility is to connect two separate mixtures together using gang valves (e.g., use a T-connector to attach both mixtures to the same airstone). Then, mix up a new batch in one rig while the other one is still going. The idea is to always have one of the mixtures going at full steam so that when one mixture quits, the other produces enough CO2 to keep your plants happy.

3) Hot water kills yeast. If you dissolve yeast in hot water (like what comes out of my gas water heater), you probably won't get any CO2 from your setup. If you've mixed things up properly, you should get CO2 production within a few hours, possibly more quickly; I've sometimes had things going 30 minutes after mixing a new batch. Here's what I do:

1. Fill a 2 cup measuring cup with hot water, and dissolve the sugar in it. If you use a cup with a spout, you can pour the mixture directly into the soda bottle without a funnel (one less gadget to clean!)

2. Add three more cups of cold water to the mixture and shake it up. 3. Dissolve the yeast in a cup of cold water and add to mixture. I've only used bakers yeast, but others should work

too. 4. Add more cold water to mixture to fill to desired level. Shake the mixture well.

5. Let sit at room temperature for a few hours until the mixture reaches room temperature. That's often all the time that is needed to get initial CO2 production going. I feel safer connecting my setup to the tank *after* I know that it is producing gas and won't suck water out of the tank.

4) Some batches of yeast take longer get going than others. For example, yeast stored in a refrigerator takes longer to become active than yeast stored at room temperature. Letting the yeast sit out at room temperature overnight before adding it to your mixture reduces the startup delay. Another suggestion (from homebrewers) is to hydrate the yeast in a cup of warm (80 degree) water for 20 minutes before adding it to the sugar mixture.

5) Nicholas Plummer reports that most people who advocate using a cannister filter as a reactor seem to have Eheims. When he tried bubbling gas into the intake of a fluval 203, the gas made the impeller rattle loudly when a bubble formed at the top of the cannister. He suspects that the slightly poorer design of the Fluval is to blame.

Even without funneling CO2 into the filter, he gets the same effect (but to a lesser degree) late in the day. The water becomes so saturated with oxygen from photosynthesis that it starts to bubble out in the cannister. It reenters solution during the night and is always completely gone by the next morning. Perhaps the slight agitation of the water entering the cannister through an eheim surface extractor causes oxygen to precipitate out of solution.

7) Some folks appear tempted to turn off the CO2 production at night and back on again in the morning. After all, plants consume oxygen at night and produce more CO2. This is a mistake. It is better to keep the tank's CO2 concentration relatively constant because a drop in the dissolved CO2 concentration leads to an increase in pH. Neither plants nor fish seem to appreciate rapid pH swings.

8) Several persons report the appearance of an apparently harmless white film on their CO2 airstones. I have not witnessed this in my tank and am not sure of its cause.

9) I am still experimenting with exact ratios of sugar, yeast and water. In my system, the rate of CO2 production is relatively steady for a number of days, but then drops precipitously (from several bubbles a minute to no production in 24-48 hours). I suspect that the yeast exhausts some trace element or other critical ingredient. Yeast needs a number of elements, including nitrogen (e.g., ammonia but not nitrate), magnesium, phosphorous, potassium, calcium, zinc, iron and copper. My initial hypothesis was that a buildup of alcohol limited yeast production. However, a homebrewing friend reports that it would take roughly 3.75 cups of sugar in a 2-liter bottle to produce enough alcohol to reach a concentration of 15%, the point at which no strain of yeast can survive. As another data point, I have been running a mixture now for over six weeks that is still producing an adequate amount of CO2. I have no explanation for the longevity of the current mixture. I used the same general recipe that previously worked for only two weeks.

10) It should be possible to culture a new mixture using yeast from a previous batch. Simply save the sludge that collects at the bottom of a mixture. The top layer of sludge, which should be a bit lighter in color, consists of live but dormant yeast cells. The darker layer underneath is dead cells. I have not tried this myself. For more information, look towards the homebrewing field.

RESULTS

After some 15 years of mixed success at growing plants, I now have a jungle. I have to trim the growth in my 55g tank every 1-2 weeks. If I don't, plants completely cover the surface of the tank preventing light from reaching the lower levels. I have so many plants I'm throwing them away! My setup consists of:

55g tank. 2 40W bulbs (two 18-month old tritons). Temperature held at 78 degrees. UGF driven by 2 Aquaclear Powerhead 301s. Layer of floss between gravel and UGF plate. Some plants in gravel, some in "plant plugs", others in clay/plastic pots containing potting soil. Hard, alkaline water (tap pH 7.6+, GH 140-190 ppm). 2 corys, 3 kribs, 5 otocinclus affinis, 2 pearl gouramis, 2 blue rams, 4 medium angels and an angelicus cat. DIY yeast CO2 rig, airstone, and plastic CO2 bubble trap (not connected to powerhead) Regular addition of trace elements with iron.

Without the CO2 rig, the measured CO2 concentration in my tank is about 1-2 ppm (according to the Lamotte CO2 test kit). With the CO2 rig, measured concentration ranges from 5-20 ppm, depending on what my bubble rate is. With CO2 injection, my pH drops from 7.8 to about 7.0 (at a CO2 concentration of 20 ppm). When the CO2 runs out, pH rises again. Warning: The pH change can happen in less than 24 hours, and some fish may suffer. To avoid this problem, hook up a new mixture before the old one has completely run out.

I recently counted over 25 species of plants in my 55g tank. About 15 species I've had for eight months, the rest for about four. Most of the plants are doing extremely well. My major successes include hornwort, vallisneria, pennywort, elodea, foxtail, wisteria, ludwigia, java fern, rotala rotundifolia and both hygro. polysperma and carymbosa, which I throw out regularly.

Other successes include willow moss, several swords, various cryptocorynes, alternanthera lilacinia, rotala macrandra, sagittaria, plus a few things I haven't been able to identify. My anubia nana doubled its size in four months, more growth than the entire previous year. It's growing a new leave every week. Last month, it bloomed for the first time.

Some of the plants are not doing much, but they haven't died and rotted either. Part of the problem is that I don't have enough light reaching the bottom. The faster growing plants outcompete everything else. I have also witnessed a number of plants near the bottom struggling weeks to grow a few inches (even when under direct light), but after reaching a height of four or five inches, growth takes off. I'm convinced now that more light would help.

My only true failure is cabomba. I had it growing very well for 2-3 months (I was throwing it away I had so much), but then growth just stopped. The plants got stringy looking and the leaves fell off. Since then I have learned that I probably don't have enough light for cabomba in my tank and my water is warmer (78 degrees) than ideal.

It is now apparently also the case that my tank doesn't contain enough nitrogen to keep all plants growing at full steam. In the three months since purchasing a sensitive Lamotte nitrate test kit, nitrate levels have always registered zero. It is also apparent that some plants are growing at the expense of others. For example, elodea and foxtail growth was prolific at first, but now grows only slowly.

SUMMARY

In summary, the described sugar, yeast and water CO2 injection system provides an inexpensive way to experiment with CO2 in a plant tank. It is particular attractive to those interested in trying CO2, but skeptical that benefits justify the cost of conventional systems. Although a bit more hassle to maintain than a proper tank-driven injection system, I do not find the burden to be excessive. Although I could afford to purchase the more expensive conventional system, I have little inclination to do so at this point. I spend much more time feeding my fish and trimming plants than I do fiddling with my rig.

Thomas Narten16 Leto Rd.Albany, NY 12203518-869-6958narten-at-cs.albany.edu

Water Hardness

by larry/creative.net (Larry Frank) Date: Tue, 16 Dec 1997

After reading all the posts for hardness and alkalinity, I tried to go back through the aquarium literature that I have, and make some sense of all the different definitions, also tried to understand how all this affects CO2 addition. The following is what I came up with. My thanks to Dave (eworobe-at-cc.UManitoba.CA) for his help with understanding alkalinity. Any errors are mine not his.

Water Hardness

All fresh water sources contain calcium and magnesium in varying quantities. These are cations with a 2+ charge. They form salts with anions which have a negative charge. The most important of these are bicarbonate (HCO3

- ; carbonate CO32- ; and sulfate SO4

2-.

General Hardness (GH) measures the cations (+ charge); for calcium and magnesium.

Carbonate Hardness (KH) Refers to only the bicarbonate, and carbonate anions(-charge); it does not measures the sulfates and other anions.

Carbonate Hardness is a confusing term because it does refer to hardness, but rather to the alkalinity (the ability of a solution to resist a pH change with an addition of an acid.) from the carbonates and bicarbonates. Other anions (such as hydroxide, borates, silicates, and phosphates) can contribute to the alkalinity. To be absolutely correct, you should NEVER use the term 'KH'; however, this is often refered to in aquarium literature. It should

be noted that it is the bicarbonate/carbonate buffering system which provides the majority of the alkalinity in aquariums plant aquariums.

KH and GH are usually are close two each other, but the GH can be the same, higher or lower to the KH depending on the Cations and Anions in the sample. For example, a large amount of NaHCO3 would raise the (KH) and not effect the (GH). A large amount of MgSO4 would raise the (GH) and not the (KH).

Usually, in fresh water most of the cations are calcium and magnesium (In a 3:1 ratio) and most of the anions are carbonates. The levels for (GH) and (KH) will often be similar.

Units

It would make sense to measure the general hardness in # of ions/liter or molarity, but this is not used. The common units found in the literature are degrees of general hardness dGH (GH) from the German system or ppm Ca from CaCO3 . Carbonate hardness (KH) is a term which has nothing to d with hardness, rather it is the amount of carbonate or bicarbonate equivalents which effect the alklinity or acid buffering capacity. (KH) is equated to ppm CO3 from CaCO3

Converting from dGH and dKH to ppm CaCO3 can be accomplished by multiplying by 17.86

How the conversion factors were derived: (GH)

By definition, 1dGH = 10 mg/liter CaO

Atomic Weight Ca = 40, O = 16, CaO = 56

So 10 mg/liter CaO contains 40/56 *10 = 7.143 mg/liter of Ca

By definition ppm Ca is not for elemental calcium but for ppm CaCO3.

Atomic weight CaCO3 = 100

So 7.143 mg/liter of elemental Ca would be expressed as 100/40 * 7.143 = 17.8575 mg/liter(ppm)CaCO3.

1dGH = 17.86 ppm CaCO3 and 7.143 ppm Ca2+.

(KH)

1 dGH is defined as 10mg/lit CaO this can be related to ppm of CaCO3 as in above. Now the definition for dKH must have come from the amount of carbonate in 17.86 ppm CaCO3 which has nothing to do with GH wich is defined by CaO! Historically GH must have been defined first in terms of CaO; hardness in terms of ppm CaCO3 second, then KH third?

1dKH = 17.86 ppm CaCO3

From above; 1dKH = 17.8575 mg/liter CaCO3. 7.143 mg/liter of this is Ca, the rest ;(17.8575-7.143)= 10.7145mg/liter CO3

1dKH = 10.7145 ppm CO3

For bicarbonate:

CaCO3 forms Ca(HCO3)2 in water at pH less than 10.25 . (Two bicarbonates are formed from each carbonate ion):

CaCO3 + H20 + CO2 ---> Ca(HCO3)2

CO3 mw = 60 HCO3 mw = 61

Therefore 10.7145mg/liter CO3 from CaCO3 (each CO3 carbonate anion forms two HCO3 bicarbonate anions; 61/60*2 *10.7=21.8 mg/liter HCO3

Another way to calculate this is using molarity:

1dKH = 17.86 mg/liter CaCO3 mw CaCO3 = 100

17.86 mg/liter CaCO3 = .179 m Mole CaCO3

This will form 2* .179 m Mole = .358 m Mole Multipling moles *mw will give mg:

0.358*61(mwHCO3) = 21.8 mg/liter HCO3

1dKH = 21.8 ppm HCO3

How to use these conversion factors:

If you have alkalinity in ppm or hardness in ppm divide by 17.86 to get degrees.

If you want to raise the alkalinity by 1dKH using CaCO3: use 17.86 mg CaCO3

If you want to raise the alkalinity by 1dKH using NaHCO3:

mw Na = 23 mw HCO3= 61

mw NaHCO3= 84

1dKH= 21.8 ppm HCO3 21.8 *84/61=30 mg/liter of NaHCO3

using molarity: 0.358 mMoles * 84(mwNaHCO3) = 30 mg/liter of NaHCO3

CO2, pH And Alkalinity from Carbonates

CO2, pH and carbonates are all related by the following three equations:

1. CO2 + H20 <------> H2CO2 (Carbonic Acid)

2. H2CO2 <------> H+ + HCO3- (Bicarbonate)

3. HCO3- <------> H+ + CO3

2- (Carbonate)

Example of how increasing carbonates will either raise the pH or need counterbalancing CO2 added to maintain the pH level.

If NaHCO2 is added to aquarium water the additional carbonate ions will cause a shift to the left side of equation (2). This will form more carbonic acid extracting a H+ ion and thus raising the pH. The additional carbonic acid will drive equation (1) to the left creating CO2 which will dissapate out of solution bringing equalibrium at a higher pH. In order to maintain equalibrium at the original pH equations (1) and (2) must be shifted back t the right. This can be accomplished with the addition of more CO2 into the aquarium. (Equation (3) becomes important as pH approches 10.25)

These relationships are expressed in the familliar Chart with KH/pH and the amount of CO2 needed in solution to maintain a specific pH. The higher the amount of carbonates/bicarbonates in the aquarium, the more CO2 is needed to maintain a specific pH.

pH 6.0 6.2 6.4 6.6 6.8 7.0 7.2 7.4 7.6 7.8 8.0 .........___________________________________________________KH0.5 | 15 9.3 5.9 3.7 2.4 1.5 .93 .59 .37 .24 .151.0 | 30 18.6 11.8 7.4 4.7 3.0 1.7 1.2 .74 .47 .301.5 | 44 28 17.6 11.1 7.0 4.4 2.8 1.8 1.11 .70 .442.0 | 59 37 24 14.8 9.4 5.9 3.7 2.4 1.48 .94 .592.5 | 73 46 30 18.5 11.8 7.3 4.6 3.0 1.85 1.18 .733.0 | 87 56 35 22 14.0 8.7 5.6 3.5 2.2 1.40 .873.5 | 103 65 41 26 16.4 10.3 6.5 4.1 2.6 1.64 1.034.0 | 118 75 47 30 18.7 11.8 7.5 4.7 3.0 1.87 1.185.0 | 147 93 59 37 23 14.7 9.3 5.9 3.7 2.3 1.476.0 | 177 112 71 45 28 17.7 11.2 7.1 4.5 2.8 1.778.0 | 240 149 94 59 37 24 14.9 9.4 5.9 3.7 2.410. | 300 186 118 74 47 30 18.6 11.8 7.4 4.7 3.015. | 440 280 176 111 70 44 28 17.6 11.1 7.0 4.420. | 590 370 240 148 94 59 37 24 14.8 9.4 5.9

CO2 mg/liter

CO2 in excess of 40mg/liter is harmful to fish. Using this chart the alkalinity of the water from bicarbonates is balanced against a desired pH using CO2 to control the pH, making sure a unhealthy amount of CO2 is not called for.

Hardness

by George Booth <booth/hpmtlgb1.lvld.hp.com> Date: Wed, 17 Dec 1997

Great summary, Larry. I would only like to add the following for those who don't read between the lines:

1. The pH/KH/CO2 table is based solely on "carbonate hardness". 2. All KH test kits that I know of measure alkalinity, not true KH. 3. The CO2 value you get from the table will NOT be accurate if there are other sources of alkalinity in your water

besides bicarbonate. 4. Even CO2 test kits are not accurate in the presence of other sources of alkalinity (phosphates, for sure).