DE FIlter draining when Pump turned off


Active member
Aug 16, 2015
Bryan, Texas
As per the title of the thread, my DE filter is draining out every time the pump is turned off, and the water coming back out of the skimmer (as evidenced by DE in the pool). Once you get the prime reestablished and the air out of the system, the pump basket fills back up all the way to the top of dome (it's a Hayward system) and seems to run fine, then when you turn it off, the process starts all over again.

Needless to say, the status quo isn't working, so I trying to figure out what to do (short of calling out the pool company). Is this a suction side leak, or is this something else, such as a bad multiport valve (we're on the second one)? A bad union or pump T-gasket? Bad pump lid, or bad pump O-rings? Or none of the above? Of course what really worries me is an underground leak (although would that much air get into the system that quickly if underground?), as we have a number of trees in the yard, and have had saplings grow up (and alongside) the mains at the pad. Or is it a possibility that there is a leak in the filter itself?

The system itself is almost twenty years old, so I'm guessing age (along with the associated wear and tear) is no doubt a factor as well.
Last edited:

Rancho Cost-a-Lotta

Silver Supporter
Apr 10, 2018
Rancho Cucamonga, CA
Pool Size
Salt Water Generator
SWG Type
CircuPool RJ-45
If your not seeing air in the filter basket once the pump primes, your leak is likely on the pressure side, after pump. Are you seeing any water leaks when the pump is on? Try shutting down the pump during a quiet time and listen carefully for an air leak. It could be the main filter o-ring or MPV valve (spider gasket). Check the fitting on the filter gauge and air bleed valve.
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