My inlaws bought a house that came with a rectangular pool. There are two outlets in one wall, one in the deep end, one in the shallow end. The skimmer is in the deep end. I have only ever seen water coming out of the deep end jet when the pump is running. The pool company that closes for them had no idea what the other jet was for either.
The pool skimmer has two inlets? (two holes) in the bottom. When the pump is running, there is only suction in one of the holes. I opened the pool for them recently, and on a whim, I shot a jet of water with the garden hose through the other inlet in the skimmer. Lo and behold, water shot out of the jet in the shallow end.
Any idea why the pool would be plumbed like this? What purpose would having the second skimmer hole plumbed to a pool jet serve?