Slow Air Leak / Suction Side


New member
May 18, 2021
Phoenix, AZ
Looking for some help and or ideas... I am going crazy!

About 3 months ago we had our pool remodeled. part of that process was moving all the equipment and a decent amount of replumbing with all new pumps, filters etc. Ever since starting up my pool I have had a slow air leak on the suction side that I cannot nail down and it is driving me nuts!

The Problem

When the automation primes the pump (2 minutes) the filter basket will eventually clear of air and full of water. After about 10 minutes of running the pump if I look at the filter basket there will be a golf ball sized amount of air in there. If i come back an hour later there will be 1" of air at the top of the filter basket. There is a slow air leak somewhere that I can't find.

What I have checked.

  • I do not think the leak is coming from anything past (pool side) the diverter valve (skimmer & vacuum). The leak appears to be the same no matter if it is on the simmer inlet or vacuum.
  • I have tightened down all the bolts on the back of the pool pump to the motor and impeller housing.
  • I have tightened down the pump drain plugs.
  • I have tightened down the screws on the diverter valve.
  • I do have an orp & ph sensor (Hayward sense and dispense). If I close the valves so no water passes through the sensors and sensor manifold the same slow leak appears to be there.
  • I have taken the pump out, inspected the 2" union washers and re-tightened (with a wrench) everything.
  • I have inspected the filter basket lid o ring and it looks fine.
  • There are no water leaks anywhere... just air slowly filling up the filter basket.

Here are some pics of my setup (please excuse the dirt and mess, still working on a larger home remodel).



Gold Supporter
LifeTime Supporter
TFP Guide
Jul 3, 2013
Southern OK
Pool Size
Salt Water Generator
SWG Type
CircuPool SJ-40
try pulling the pump lid o ring and cleaning it and the lid with dawn dish soap and then lube the o ring with lots of lube and reinstall... that is usually where it is at..

if that does not do it it is in the pipes and you only have 2.. you can try to seal with this stuff along the edges of every pipe transition like this, the black lines.. if there is a hole this will fill it.. it may not look pretty but you can paint it afterward.. I had a pressure side leak 8 years ago and it is still closed :)

if that does not work it is somewhere else and I am out of ideas...

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