PC202: SAND FILTERSSMART START Pool School

SAND FILTER OPERATIONS

➤ Sand filters comprise approximately 29% of the total installed filter types in the US, coming in second only to cartridge filters.

➤ Of all filter types, sand filters work to the largest filtering capacity, approximately 30-40 microns.

➤ Alternate replacement media types like VitroClean crushed glass can provide even better filtering results without any equipment replacement.

➤ Media lifespan for sand filters is roughly 3-5 years, depending on usage and care. Heavy-use pools may need to replace media more often.

HOW SAND FILTERS WORK➤ Sand filters have two main pieces: the filter tank and the multiport valve.

➤ The multiport valve controls all operations of the system; this is what determines which way water moves through the filter tank.

➤ The valve can be installed either on top of the tank—called top-mount—or on the side of the tank—called side-mount.

➤ Multiport valves are equipped with a sight glass and pressure gauge to aid in regular cleaning, known as backwashing. The filter should be backwashed when pressure increases 8-10psi above clean pressure, or the reading on the gauge when the sand is clean and fresh.

➤ Make sure to always go in the same direction—either clockwise or counter-clockwise—when changing settings on the multiport valve to prevent uneven wear inside the valve.

➤ Always turn off the pump before changing settings on the valve! Damage can occur if you try to change settings on the valve while the pump is running.

➤ The tank should be at least half full of filter media but no more than about 2/3 full; this ensures that water can move through the system—though not too easily—while the sand traps debris.

Left: example of multiport valve. Right, top: example of side-mount sand filter, valve not shown. Right, bottom: example of top-mount sand filter, valve shown.

SETTINGS: FILTER

➤ This is the setting that will get the most use. In this setting, water returns to the pool.

➤ Water enters through the valve and goes to the very top of the filter; pressure from the pump pushes the water down, through the sand. Debris is captured as water is pushed through the sand.

➤ Water is collected in the laterals, or fingers, at the bottom of the unit.

➤ Water then travels up the stand pipe and back into the pool.

SETTINGS: BACKWASH

➤ This setting is frequently used to relieve an increase in pressure and remove debris in the filter. In this setting, water does not return to the pool and instead goes out a waste line.

➤ Water enters through the valve and goes down the stand pipe and through the laterals.

➤ Water is pushed up through the sand, grabbing debris trapped in the sand as it goes.

➤ Water then passes out the waste line, taking debris with it.

SETTINGS: RINSE

➤ This setting is used after backwashing to help compact the sand back into position after backwashing and to clean out any remaining dirty water. In this setting, water travels out the waste line.

➤ Water enters through the valve and goes to the very top of the filter; pressure from the pump pushes the water down, through the sand. Debris is captured as water is pushed through the sand.

➤ Water is collected in the laterals at the bottom of the unit.

➤ Water then travels up the stand pipe and out the waste line.

SETTINGS: WASTE

➤ This setting is used primarily for vacuuming large debris or draining out volumes of water. In this setting, water travels out the waste line.

➤ Water enters the valve and travels out the waste line. Water does not travel through the sand in this setting, instead bypassing the sand, laterals, and stand pipe.

SETTINGS: RECIRCULATE

➤ This setting is little-used in filter operation; it is primarily used for troubleshooting to eliminate or identify the sand filter as a cause of a leak. In this setting, water returns to the pool.

➤ Water enters the valve and then travels back to the pool; water does not travel through the sand, laterals, or stand pipe.

SETTINGS: CLOSED

➤ This is a rarely-used setting on the filter; water does not travel out of the multiport valve in this setting.

➤ Make sure not to leave the filter on this setting when the pump is operational; this can cause damage to your equipment!

FINAL NOTES

➤ Older filters may not have all the settings presented here. That said, all sand filters should have, at the very least, a filter and backwash setting.

➤ Some valves have a WINTERIZE setting; this is used at closing to drain water out of the valve and to prevent the inner parts of the valve from freezing.

➤ If you aren’t sure how to operate your filter, talk to a specialist at The Pool & Spa House or your pool builder to learn how to operate your sand filter.

THANK YOU!Click NEXT to continue!