Expert: Deb Carney - 7/10/2006

Question
I recently purchased a hayward pro series sand filter for my inground pool. After shutting off pump for backwashing, vaccuming, etc. filter loses pressure and I have to add water to pump to regain pressure. Filter is above pool level. Will ball valve or check valve fix problem?  

Answer
Hi Steve, it depends on how much of a pitch is on the suction line if it is too much then the water will only drain back to the pool you are losing your prime when you shut off the filter because of this pitch in the line. I would try the ball valve or check valve. Did your other filter have this problem too.