Hi,
I bought a house with pool and have a question: My pool sand filter just after backwash shows about 15psi and even running two weeks without backwashing still stays at about the same level. Is 15psi not too high for clean sand filter? Other people here talked about 10-12psi. Also, when I turn off my pump for a night, sometimes filter preassure goes down to 0, but sometimes it stays at exactly the same level as it was with pump on - about 15psi. Is that normal?
Thank you very much for your help.