Quote Originally Posted by xoroniox
Thanks for your help, so to check this i would swim to down to the main down, does it matter if the filter system is on or off? and open the main drain cover and check for the valve because i am not sure if my pool has that valve or not. if it does lift the valve and close it and hope that does something.
I would think that any IG pool that has a chance of ground water being higher than pool water will have a hydrostatic valve. This is what keeps the pool from becoming a boat and rising out of the ground if the ground water gets higher than the water in the pool. You might go to a pool store and get a look at one so you can see that it is a spring loaded one way valve that should let water in but not out. Mine is part of the main drain box. Good luck, Paul