Swimming Pools

How Do I Backwash My Swimming Pool Filter?

This is a common question among new owners of swimming pools. It's a simple maintenance procedure but it should none the less be done the right way. If it is not done regularly, your pool's filter equipment and water quality will suffer. Note that only sand and DE filter systems can be backwashed, cartridge types do not need backwashing. Here is a brief overview of how to backwash your pool filter.

Sand filter: when the contaminates in this type of filter build up, they will impair water flow such that the pressure reading will rise around 8-10 psi above normal. When this happens, it's time to backwash the system. How often this will need to be done will depend on your particular pool and how frequently it is used.

Firstly, to avoid damaging the plumbing or valve, turn off pump. For extra safety, turn off the power completely. Next, turn the valve round from 'filter' to 'backwash'. Take care not to damage the valve seal by making sure to fully depress the valve handle.

Now make sure that the waste hose is directed to a suitable area where the waste water can flow without causing mess or damage. Make sure, too, that the hose does not have any kinks in it. Turn the pump back on and allow it to run for at least two minutes. Watch the sight glass for the water to turn from cloudy to clear.

When the water in the sight glass is nice and clear, turn the pump off, then turn the valve over to the 'rinse' cycle to rinse out the sand. Turn the pump back on for one to two minutes. During this procedure, the sand in the filter will be reset.

Also, any dirty water remaining in the filter will be rinsed out to prevent it from entering the pool. Turn the pump back to 'filter', then re-start it. Check that the pressure has returned to its normal level. An important point to bear in mind here is that pool filter sand must be used, not regular sand!

DE filter: first, turn off the pump. Now make sure that all of the pool's baskets are cleared of debris.

Turn the valve over to backwash mode. Make sure the backwash hose is directed to a suitable area for the waste water and old DE to run out. Make sure the hose is free of kinks.

Now run the pump for about a minute and watch the sight glass for water to run clear. When it's clear, turn pump off and return to filter mode. Now run the pump again. Repeat the backwashing cycle two more times. When done, it's time to replenish the system with fresh DE.

Simply add the required amount into the skimmer while the pump is running (in filter mode). Check filter guidelines for quantity of fresh DE needed for swimming pools. Caution: DE can be very irritating to sensitive parts of the body so take care not to breathe it in, get it into your eyes or into broken skin. It is also a carcinogen, so again, handle this substance with great care.