Cannot find air leak

Jun 7, 2017
Hello fellow pool owners!

Last week I bought and installed a new pool pump.
The pump has issues with priming and has a lot of air bubbles in the basket area.
Sometimes the pump will run fine with no air bubbles from the return jets (still does have air bubbles in the basket), but as soon as there are about 5 leaves in the skimmer basket, air will start coming out of the return jet too.
Only the jet closest to the pool though, the furthest one never experiences air bubbles.

I had to redo the piping and all fittings for this new pump since it is bigger than my old pump.
Plus the new pump is 1.5 HP for a 20000 gallon pool with 1.5 inch piping.
However, the inlet fitting for the pump is converted from 1.5 to 2 inches since that is how it was on the old pump.
Could this entire new setup be the cause of air bubbles?

Things I have tried so far:

clearing the skimmer line
lubing every single O ring with silicon grease
wrapping every thread in 5 layers of teflon tape
putting several layers of glue on all new pvc piping connections
shaving cream test, did not help
wrapped all the connections in tape (pretty sure this is useless but hey I'm desperate)
looking for water leaks when shutting the pump off, there are none
opening the multiport valve and cleaning it
removing both drain plugs and wrapping them in multiple teflon layers

I'm running out of ideas to try, does anyone have any other suggestions I can try to find the air leak?
Since the pump is in an inside area it's hard to do the garden hose test since the room will flood quite swiftly.

Also, when I close the multiport valve and skimmer line and disconnect the piping I can hear the sound of air hissing in the pipes (I think both inlet and outlet), but can't trace where it's coming in.
Furthermore, it doesn't appear that I'm losing water.

My setup:
20000 gallon pool
Pentair P-SFL-153 pump
Old Kripson filter
1.5 inch piping
(Please find pictures attached in imgur of my setup)

Imgur: The magic of the Internet

Any help is greatly appreciated!

Texas Splash

Mod Squad
LifeTime Supporter
TFP Expert
I generally like a good air leak challenge, but in your case, you have done some homework already. So I'll toss a couple more ideas out there for you to consider just in case we get lucky:
- You mentioned lubing "every single o-ring", but I still want to confirm .. that includes both the clear lid O-ring and any pump drain plug O-rings correct?
- Do you have a main drain?
- Is that blue handled shut-off valve the only one before the pump?
- Do you have the air problem even if you change from filter to recirculate?
- Can you clarify this comment please:
when I close the multiport valve and skimmer line and disconnect the piping I can hear the sound of air hissing in the pipes
I understand closing off the MPV and skimmer (blue handle), but what piping are being disconnected to make that air sound?

I commend you on that equipment set-up. Very nice and clean work you've done there. :salut: Now let's find that leak.

- - - Updated - - -

Oh, and let's not forget ..... the pool water level is high enough AND the skimmer weir door (flap) operating okay?


Well-known member
Jun 26, 2016
boiling springs, SC
I had the same problem with the pump getting it’s water from the skimmer pipe but not the bottoms drain. Had a guy come do a pressure test on it at 25psi and it would leak down with in secs. My leak is under the concrete pad at the pool [emoji24]