I just had Leslies install a new Hayward Filter. The pressure builds up after about 4 hours. Pool is clear and readings are good. I backwash and no dirty water comes out which is expected if water is clear and chemistry is good. I think I might have a small leak at the bottom of the pump. Am I correct that leaks would make the pressure go down and not up? I am also wondering if I put back enough DE when I first backwashed a couple of times with the new filter but again this wouodnt build up ressure? I never know how much DE o put back in becsaue I dont know how much went out.