I have an 18.5 by 36.5 in ground pool with a fermicalite base. I have unground water problems where the water at times can move my liner. The pool company recommended installing two hydrastic values in the low end. Values with sit in 18" by 18" inch basin (would have to cut the base of the pool) and when basin filled up the water would be dispersed into the pool. Can you install in existing pool and do they work? The other solutions was installing a sump pump underground in the low end and have a vent in the wall so when the water got between the liner and pool wall the sump pump would then pump out all the water
Thnks
Thnks