Cox Pools Blog


Filter Maintenance


March 9, 2018


There are two basic types of filters…sand filters and element or cartridge filters. 


Sand Filter: Water comes out of the skimmer on the side of the pool and into the pump, which pumps water into the filter. The way contaminants are removed from the water is through sand, which captures the dirt. The water is pumped back into the pool, clean and clear.

As the dirt gets trapped, it starts to cake and pack the sand together too tightly, making the filter less effective and building up pressure in the filter. Check the pressure level on the pressure gauge at the top. When this happens, it is time to backwash. You’ll need to back wash about once a month or immediately when the pressure gauge reaches 30. Not more often than that because your filter will be less effective.


Backwashing causes the water to flow backwards through the sand, loosening it up and cleaning out the dirt through the side port. 


Here’s how. 

Normally, your filter will be in the filter position, but for the purpose of backwashing, you’ll need to turn the valve on the filter.  Make sure the pump is off each time you turn the filter valve position.  


Take your blue backwash hose and attach it to the side port. You can direct the end of the hose down the driveway so that none of the water gets on your lawn.  


Turn the filter valve to the back wash position and turn the pump back on for about 2 minutes. Once the water starts running clear out of the backwash hose, turn the pump off and the valve to rinse position. Rinsing just helps pack the sand back down and still allows the water to exit through the port and down the backwash hose.  Once you turn the valve to rinse, turn the pump back on for another couple of minutes.


When you are finished, turn the pump off, the filter valve back to filter, and remove the blue backwash hose. You can now return to normal pool operation by turning the pump back on.


There are four other positions that aren’t used as often:

The Waste position allows you to suck water from the bottom of the pool through the pump, bypassing the filter, and out the side port. This would be used if you are cleaning the pool with large amounts of debris.


The Closed position would be for pump maintenance, it keeps water from coming back in.

The recirculate position causes water to come through the pump and back into the pool without going through the filter.


The Winterize position is used more up north, but helps keep the valve head from freezing.


Cartridge or element filter: This is the other type of pool filter, a cartridge or an element filter. These are better than sand filters because they have to be cleaned less often, and they are more effective at cleaning out the tiny particles.


Just like a sand filter, they do need to be cleaned when the pressure gauge reaches 30, or about once a season.  


To clean, you will want to remove the filter.  Use a low pressure water hose and wash the filter from the inside out, removing all the particles. Then you’ll want to clean the outside of the filter with the hose. 



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