I just bought a house is AZ and it has a pool. For some reason I can hear air inside my pump and ts pretty loud. I cannot see air through the basket lid, but I can hear it. I replaced all the seals in the motor and pump housing, replaced the Jandy valve seals, replaced the basket lid oring, took my DE filter apart and cleaned it, poured water all over the connections to see if it would go quiet, and I still hear the air. My psi is at about 12. When I turn the sprays on in the pool, the pump goes quiet and the psi jumps to 30 and water comes out of this open pipe coming out of the ground next to the filter. What is that pipe? I have a robot that cleans the bottom of the pool and when I turn that all the way on, a massive amount of air gets into the pump and I can see it through the basket lid. But still when I turn the sprays on and the robot on full blast together, the pump still gets quiet.

Bottom line is the pump always gets quiet when I turn the sprays on and it doesn't matter what else I have on (robot, skimmer, etc.), but water comes out of this open pipe that I have no idea what it is. Is my pump too big for my pool? I am at a loss. Thanks