Filtration is one of the most important factors in your pool’s circulation system to keep it clean. There are three types of pool filters available for pool owners. Sand Filters, Cartridge Filters and DE Filters. It is important to know what filter you have in your pool and how to maintain and operate it. Each of these pool filters has its own advantages and disadvantages. With whatever pool filter you choose, it’s important to consider the proper size. Proper size refers to the volume of the pool and the size of the pool pump.

Sand filters:

Sand filters work by pushing water through a bed of sand to the sides. Sand filters generally have the advantage of being reliable and easy to operate. Sand filters are capable of continuously filtering water without turning off the pump for days and days. As long as the proper water balance is maintained along with regular cleaning cycles, the sand inside the filter will be good for up to 10 years. If you have trouble keeping the water clean and clear only, change the sand as a last resort; other pool chemistry issues are likely the cause.

Backwashing your sand filter:

When the filter gets dirty, pressure will build up, and you can see this on the pressure gauge. When the pressure gauge reads approximately 5-7 PSI above normal operating pressure, you know the filter is dirty and it’s time for a backwash. Backwashing is a simple process. The backup wash is performed by first turning off the pump. Note: Always turn off the pump while moving the multiport valve on the filter. Once the pump is off, turn the multi-port valve on the filter from the ‘filter’ position to the ‘backwash’ position. Once the filter is in the backwash position, turn the pump back on. The pump then reverses the water through the sand. Dirty water is sent down the waste line (usually to the yard). High concentrations of chlorine can kill your lawn, so it is important to know what the chlorine level is in your pool while backwashing. A range of 1 to 2 ppm should be safe to avoid killing the weed. Once the water comes out, the drain line changes from dirty to clean (it can take up to 3 minutes). Turn off the pump. Once the pump is off, move the multiport valve from the backwash position to the flush position. Turn the pump back on and let it run for about 20 seconds. Then turn off the pump and move it to the filter position.

Let’s recap the steps of backwashing:

Filter position-> Pump off -> Backwash position-> Pump on for 2 min. -> Pump off -> Rinse position-> Pump on for 30 seconds -> Pump off -> Filter position

Diatomaceous earth filters:

Diatomaceous earth filters use screens on the inside coated with diatomaceous earth or DE for filtration. DE filters have the advantage of filtering even the finest particles or microns. However, they have been considered the most complicated to operate. For a DE filter to work properly, it must be turned off for about 4 hours every day. This is to allow the DE to fall off and re-coat when the pump is running again.

Backwashing a DE filter:

Like sand filters, they also require backwashing when pressure rises to approximately 6 pounds above normal operating pressure. After backwashing, you must coat the filter screens with DE again. This is done by feeding DE through the skimmer to be pumped into the filter tank. DE is a white powdery substance that must be purchased at the pool store. About twice a year the DE filters should be removed and the grids cleaned. Most DE filters have a multiport valve that is used for backwashing. Backwashing is a simple process. Backwashing is done by first turning off the pump. Note: Always turn off the pump while moving the filter valve. Once the pump is off, turn the multi-port valve on the filter from the ‘filter’ position to the ‘backwash’ position. Once the filter is in the backwash position, turn the pump back on. The pump then reverses the water through the grates. Dirty water with old DE is wasted down the drain line (usually in the yard). High concentrations of chlorine can kill lawns, so it is important to know that the chlorine level in the pool is low during the backwash. Once the water comes out, the drain line changes from dirty to clean (it can take up to 3 minutes). Turn off the pump again. Once the pump is off, move the multiport valve from the backwash position to the flush position. Turn the pump back on and let it run for about 20 seconds. Then turn off the pump and move it to the filter position. Now is the time to recharge the DE in the tank. Check the filter label for the proper amount of DE to add, it should indicate how many pounds are required for a refill. Turn the pump back on and head to the pool skimmer. Slowly add the recommended number of pounds to the skimmer. It is best to make a slurry in a bucket and then slowly pour it into the skimmer to avoid clogging. At this point, it is a good idea to take a look at the return line in the pool to make sure the DE is trapped in the filter. If you have white powder spraying the return jets in the pool, then you know that you have a problem with the screens or that the valve is in the wrong position.

Let’s recap the backwash steps for a DE filter:

Filter position-> Pump off -> Backwash position-> Pump on for 2 min. -> Pump off -> Rinse position-> Pump on for 30 seconds -> Pump off -> Filter position-> Pump on-> Refill the filter with DE from the skimmer