Re: how does water get behind liner??>>>
The bottom of my pool (under the liner) is a mixture of concrete and vermiculite, it is designed to allow ground water to permiate through it to prevent it from cracking due to hydrostatic pressure or lifting out of the ground. I have a dry well under the pool which is connected (normally valved out) to the main pool pump. When the liner lifts slightly I just valve it to waste and run the pump to pump the ground water out -- works great. I would suggest this highly for anyone that builds a pool in an area with a high water table.
