Odd Observation Air in Pump Basket


Well-known member
Aug 29, 2016
Rose Hill, KS
My pump basket typically has an air pocket during normal operations... when I drain water from the pool through the cartridge filter hose fitting the air pocket slowly disappears. Typically the air pocket will reappear within one day.
What could this be?

Pool equipment is listed in my signature block.


Bronze Supporter
May 11, 2017
Twin Cities, MN
I normally have a small air bubble in my pump basket too. I think it is the air that gets trapped in the recesses of the lid. As long as you don't have bubble coming out of your returns or are loosing water I wouldn't worry about it.


Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
Bedford, TX

I agree with AftonJeeper... pretty typical with a VS pump, especially at lower RPMs..

You did not say, but I assume the air pocket is small and does not interfere with the pump's operation.

Also, that the water does not drain from the pump basket when the pump is off..


Jim R.


Well-known member
Aug 29, 2016
Rose Hill, KS
The air pocket is about 1/2", but pump operation is normal. The water does not drain when the pump is off. I had that issue awhile ago and resolved it with o-ring lub on the filter and pump basket o-rings.