I just backwashed my filter and after doing it the pressure is the same before I did it. The previous owner said it should be around 15 psi when clean and 20 when dirty, it is 21 right now.
History: The PO showed me how to backwash nearly two weeks ago and I'm sure I'm doing it right, but I don't know if he add D.E. after he showed this to me.
Not sure where to go here.
Thanks for any help.