When and how to backwash?


Jun 7, 2010
Plainfield, IL

As some of you may know, my wife and I recently moved into a home that has a pool (details in signature). When we hooked all of the equipment up the first time, we installed the filter cartridge, sealed the filter, filled it with water, got the pump running, and we're now in the process of shocking the pool.

Over the last two days, we've vacuumed a bunch of debris off the pool floor and I'm concerned that there is a decent amount of "gunk" in the filter at this point. I also didn't clean it prior to installing it (although it looked "ok") so I'm wondering what the best way is to go about cleaning it. Is backwashing the solution? Or, do I need to drain the filter, removed the cartridge, and spray it down w/a high powered hose?

Also, along the same lines - what pressure should my gauge be reading? It seems very very low (like 2), but perhaps that's normal.

Thanks in advance!


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
A low pressure on the gauge is normal when the pump is on low speed. You want to clean/backwash the filter when the pressure on the gauge goes up about 8 psi on high speed. If you have a cartridge filter, you open it up and spray the cartridge with a garden hose to wash all the gunk off, then put it back in.

When shocking, it is common to have to clean the filter frequently, though that does depend on the relative size of the filter and the pool.


TFP Expert
LifeTime Supporter
In The Industry
May 20, 2007
SWSuburban Chicago, IL
My pressure on low is about 2-3 so that sounds normal. :)

Incidentally - it's never gone above 4 on low - and the guage doesn't tell me when the filter is dirty - the heater not working does. I'd say clean it on a normal basis every 4-6 weeks by hosing it off and then give it a good soak - per the instructions I gave your DW- at the end of the season.:)

If you want to try to hose it off tonight that might be a good idea....