How to clean a pool sand filter is one of the most important parts of your pool maintenance procedure. The filter is like the kidneys of a swimming pool. Keep the filter clean and well maintained to keep the pool clean.
Many people choose to install a Sand or Diatomaceous Earth pool filter because they are easy to clean with the built-in backwashing feature. Backwashing only takes a few minutes each week and the filter media only needs replacing every 3 to 5 years. The only drawback is these filters require more plumbing pipes than a cartridge filtration system.
Some people are turned off by the need to deal with sand or diatomaceous earth media. However, there is an alternative to replace the filter sand with polyethylene filter media which is much easier to handle.
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Clean the Pool Skimmer Basket
Always clean the skimmer basket before cleaning the filter. Otherwise, when you reactivate the pump dirt from the skimmer will pass straight through to the filter negating your filter cleaning work.
Regularly clean the skimmer basket. The skimmer basket is the first line of defence to remove items of debris from your pool.
When leaves, insects, seeds, flowers or any other organic debris enter the pool they float on the surface for a while before sinking to the bottom. The skimmer box is a suction device powered by the pool pump. Its purpose is to remove all floating debris from the surface of the pool and trap it in the basket. The skimmer box stops items of debris being pumped into the filter. Without the skimmer your filter would need cleaning much more frequently.
We recommend the use of skimmer basket filter socks to reduce the amount of dirt pumped to the filter. This keeps the filter cleaner for a longer period and increases the lifespan of the filter and sand.
Skimmer Basket Cleaning Procedure
- Turn off the filtration system
- Remove the lid from the skimmer box
- Remove the skimmer basket from the box
- Empty the basket into the garbage bin (not your garden as it will blow back into the pool). Remove the basket filter sock and discard into the garbage.
- Replace the basket in the skimmer box with a new filter sock.
- Replace the skimmer box lid
- Turn on the filtration system to the automatic setting
- Check the pressure reading on the filter gauge is normal
How Does a Sand Filter Work?
Sand filters have a semi-spherical tank half full of fine silica sand. The pump pushes dirty pool water through the sand filter where dirt and fine particles are trapped in the sand. Then the clean water from the filter is returned to the pool.
Sand filters are popular because of the simplicity of their operation and low maintenance. These filters are ideal for all sizes of swimming pool even large volumes of water.
The main advantage of a sand filter is that you backwash the filter to clean it.
When to Backwash a Sand Filter
The filter tank has a pressure gauge indicating the water pressure inside the unit when the pump is operating. When the pressure increases 10PSI above the normal operating pressure (usually indicated on the gauge) the filter has become dirty. Backwash the filter. The threshold pressure will vary between makes of sand filters so check the instruction manual for your filter.
How to Clean a Sand Pool Filter
Always consult the manufacturer’s manual for your brand of sand filter as it may vary slightly from our recommendations below.
The cleaning process for sand filters is easy because you backwash the sand in the filter. All sand filters are installed with a multiport valve to allow backwashing. Backwash the filter every week in the summer season. During the winter season you may backwash less frequently.
Follow this procedure:
- Switch off the pump motor at the power supply.
- Turn the multiport filter valve to the backwash setting.
- Switch on the pump.
- Run the pump for 2 or 3 minutes to clean the sand in the filter
- Switch off the pump again.
- Turn the filter valve to the rinse setting.
- Run the pump for 1 minute to rinse the sand.
- Switch off the pump again.
- Turn the filter valve back to the filter position.
- Switch on the pump to auto
Note: Never move the multiport valve with the pump running. The pressure will damage the filtration system. Never open the tank without releasing the pressure first using the air relief valve.
Backwashing is the only way to clean a sand filter apart from changing the sand. The water flow from the pool is reversed through the filter to flush dirt and debris away into the drain. Backwashing a sand filter is only required for two or three minutes but even for that short period of time you will lose enough water from your pool that you will need to top up with the hose for maybe 10 minutes. This shouldn’t change your water chemistry as the volume of water lost is very small.
Sand Replacement
Replace the sand every 3 to 5 years depending on the pool’s filtering requirements. Backwash the filter every week to keep the filter clean and prolong the life of the sand.
Please read our post on How to Change Pool Filter Sand
Sand Alternative
Some people choose to replace the filter sand with polyethylene filter media which filters down to 5 microns whereas sand only filters to 10 microns. This gives the pool a clearer and healthier appearance. The filter balls are reusable after washing in a washing machine.
Sand can clog the filter but filter balls won’t clog the filter and require less backwashing. The polyethylene filter media lasts up to 5 years and are more eco-friendly as they are easily disposed in the garbage.
Pool filter balls are around the same price as a bag of sand.
How Does a Diatomaceous Earth Filter Work?
Diatomaceous Earth filters work similar to sand filters except the filter media is a fine, white powder made from diatom fossils. Diatoms are a single cell aquatic plant.
When to Backwash a DE Filter
The filter tank has a pressure gauge indicating the water pressure inside the unit when the pump is operating. When the pressure increases 10PSI above the normal operating pressure (usually indicated on the gauge) the filter has become dirty. Backwash the filter. The threshold pressure will vary between makes of DE filters so check the instruction manual for your filter.
How to Clean a DE Pool Filters
Always consult the manufacturer’s manual for your brand of diatomaceous earth filter as it may vary slightly from our recommendations below.
The cleaning process for diatomaceous earth filters is easy because you backwash the filter. All DE filters are installed with a multiport valve to allow backwashing. Backwash the filter every week in the summer season. During the winter season you may backwash less frequently.
Follow this procedure:
Backwash the Filter
- Switch off the pump motor at the power supply.
- Turn the multiport filter valve to the backwash setting.
- Switch on the pump.
- Run the pump for 2 or 3 minutes to clean the sand in the filter
- Switch off the pump again.
- Turn the filter valve to the filter setting.
How to Change the Diatomaceous Earth (DE)
- Switch off the pump motor at the power supply.
- Loosen the air bleed screw on top of the filter & release the air pressure. Leave the air bleed screw partially loose.
- Open the drain plug to drain the tank.
- Open the filter tank. (Follow the manufacturer’s instructions).
- Flush out the tank with a garden hose.
- Re-install the drain plug.
- Rinse down the manifold and grids with a hose.
- Install the clean grids back into the tank, install the manifold following the manufacturer’s instructions.
- Check the O-ring and install the top half of the tank.
- Refer to the manufacturer’s instructions to add DE powder to the filter.
- The DE powder is usually mixed into a bucket of water and poured into the skimmer box and sucked into the filter. The DE mixture coats the grids and provides filtration.
Note: Never move the multiport valve with the pump running. The pressure will damage the filtration system. Never open the tank without releasing the pressure first using the air relief valve.
Disposal of Diatomaceous Earth (DE)
Do not dispose of the diatomaceous earth material into the sewer or stormwater system. Flush it over a lawn or garden.
If you are deciding what type of filtration system to install read our post on Cartridge Filters.
Conclusion
Backwash your sand or DE filter weekly to keep your swimming pool sparkling clean and ready for swimming. Reduce the need to clean the filter by installing a skimmer basket filter sock and change it weekly. Install a pool cover to keep debris out of your pool and filter. Finally, always follow your pool maintenance routine to test and balance your pool chemistry.