Problems with air bubbles returning into pool

[Poolsean]

Bubbles in the pump basket area will ALWAYS be a suction side issue (before the pump), not pressure side (after the pump), so it's unlikely a filter problem.

You can try isolating the skimmer, then the main drain, then the vaccum line to see which creates more bubbles than the other.
If it doesn't change, it's probably between the diverter valve and the pump.

Take a dripping wet dish towel and wrap it around glue joints, valves, and fittings, one at a time and see where the bubbles reduce or stop. That would help isolate the leak.

Hope this helps,.

[chrisexv6]

Something that helped me (and I believe was suggested to me here) is to have someone cycle the filter on and off (not too much, a few times) while you are watching the plumbing (including and especially the drain plugs on the pump). The water may spurt out of the leak once the suction is removed (i.e. pump turned off).

This procedure helped me trace a tiny suction leak to the drain plug in my pump (on the suction side, where the strainer basket is). Put some RTV sealant on the drain plug, let it set and no more air bubbles.

-Chris