Hello all! Long time lurker here. I am usually able to find the answer to any question I have just by searching, but alas I am stumped and may need a bit more help than that.
The past few months, whenever I am pulling suction on the "Main Drain" line, the pump makes a terrible racket and bubbles appear in the filter basket, which is resolved by shifting the valve back toward Skimmer. Here is what is stumping me...I believe the bubbles are being formed by cavitation vs. an air leak. The bubbles just appear (rather than flowing into the basket), and there isn't enough air to lose prime or anything. I still have water flow, perhaps at a very slightly reduced pressure when I open the spigot valve located on the pump outlet.
There is a valve that separates Main Drain from Skimmer (I have two skimmers, 2 deep end drain covers, 4 wall drain covers, and two hot tub drain covers) before inletting to the filter pump.
So I'm thinking clog somewhere, somehow. Now, before I drag out the toilet snake, I figure I maybe should solicit ideas on how to resolve this? My pool is 53 degrees today, so I won't be diving in and removing covers without being armed to the teeth with validation or advice. LOL
Thanks a bunch in advance!