I recently remodeled my in-ground swimming pool. New plaster, pentair variable speed pump, jandy valves, pentair 400K heater and new tiles. We also installed the split drains and a new skimmer was needed. When the house was purchased in 2010 the waterfall from the spa into the pool was a "feature" that could be turned on and off. A few months after ownership the spa would drain down to the pool level when the pump turned off. To correct the immediate problem we turned on the waterfall and the spa no longer drained. I had two estimates from pool contractors that said they would fix the check valve so that this would not happen in the future. I decided to go with a pool contractor that came highly recommended by the landscaper. The pool still has the same problem as before and the waterfall must be on when the pump is on. I'm no engineer, but this makes no sense. Suppose in summer you want to take a spa, so when the pump turns on the following morning the 104 degree water will then go into the 90+ degree pool? The contractor said there was no check valve, we had believed it was by or at the spa, not a great place to put it but in 1985 they did what they wanted to.
I would appreciate any ideas to correct this problem or should I just learn to live with it. The pool was looking old, but it held water and worked just fine with the waterfall running. I spent a lot of money to have this result.