As a rule, suction leaks aren't that hard to FIX, they are just hard to FIND.

Unfortunately, "hard to find" means, "hard to find for me!", with 30 years of pool experience. If you don't have a lot of DIY experience and understanding, it tends to mean "extremely hard to find" for you.

And, it's not the sort of thing I can help you do: suction leaks tend to be icky-picky things that get overlooked. I'll give you a list . . . but after that you're pretty much on your own.

1. If you are looking for a suction leak, you can rule out EVERYTHING on the pressure side, that is, downstream of the pump. (Including the filter!)

2. Suction leaks draw AIR into the piping; pressure leaks let WATER out of the piping. You need to keep this in mind.

3. Pumps change from suction side, just upstream of the impeller, to pressure side, just downstream of the impeller.

4. Places where I have found suction leaks include:
=> pump basket lid gaskets
=> cracked pump lids. (Cracks further down on the pump are PRESSURE leaks)
=> leaks at where pipe connects to the pump.
=> leaks at valves. (I've found leaks AROUND the valve STEM).
=> leaks at winterization drain plugs
=> leaks at any feeder or tubing that is on the SUCTION side of the pump.
=> leaks at a 'whirlpool' in the skimmer
=> leaks at a cracked skimmer.
=> leaks underground, in the piping (DISASTER!)

5. A leak like your may 'hiss' when the flow transitions from "full" to "bubbly, with little water".


. . . that's all that's coming to mind at the moment. Good luck!

PS. OVER-tightened fittings are ALSO a source of suction leaks: plastic cracks when over-tightened.

PPS. If you post pictures of your pool AND piping, something may 'jump out' at me or someone else here.