Not 100% sure this is the right sub forum so please move if necessary ....
I have a pool and a above ground Jacuzzi attached to it, it water falls into pool when the pump is running but when the pump is not running it empties into the pool by about half way.
I was told to install a check valve in the bypass line by my pool guy even though I already had one but I added another one anyway, I was told that was bad and to install another one and now I have three 1" check valves installed and it still does it.
My New pool guy ( last one was a drunk also my brother-in-law) had no clue how to fix it so he brought his Dad over and he thinks ( didn't sound confident) that I need to change the guts out on both the 2-way Ortega valves and said if its not that then he doesn't know....Great
So before I go spend a 100 bucks I figure I'd find a place like this and ask.