You might have bad bearings or maybe something stuck in the impeller.
I am going to replace both of them - new knobs, new o-rings, and new Magic Lube on it's way. Should I avoid running the pump in the meantime? Does that noise sound more like bearings than cavitation?Maybe both drain plugs are leaking.
The front one can suck in air if it is leaking.
Depends on how bad the leaks are and if the water is getting to the bearings.Should I avoid running the pump in the meantime?
Hard to tell.Does that noise sound more like bearings than cavitation?
It's on its second season.How old is the pump?
I found an installation manual for your pump - see link Refer to Installation Heading (pg 1) and subsection PIPING point #6Given his expertise and knowledge, I am leery of questioning whether he installed the wrong size pump / filter combo or that the configuration for the plumbing is incorrect. Is there any chance he did the 90 degree elbow ON PURPOSE to slow down the flow of water through the pump in order to make the pump/filter combo work well together?
Well, it’s hard to be clearer than that, huh?Note: Do not install 90° elbows directly into the pump inlet or outlet
One additional item - put a union before and after the pump which will make any future maintenance easier to remove the pump for servicing or storage(if needed).There's plenty of room for correction. Turn the filter clockwise 90 degrees. Turn the pump counter clockwise 90 degrees so that the suction has a straight run into the pump adding 12 inches. Rotate the filter/waste valve 180 degrees and pipe the pump outlet that way and still leaves you plenty of room for a future SWCG.
I say after the pump is good, before the pump is just another place for a suction side air leak.One additional item - put a union before and after the pump which will make any future maintenance easier to remove the pump for servicing or storage(if needed).