I have a 26" sand filter and I just replaced the pressure gauge on it because I thought it was bad but today when I was backwashing to waste I took notice that I had a lot more pressure. When filter was in normal mode and I held my hand over the return jet I could barely feel any pressure so I backwashed the filter and after that I had a lot of pressure. I was told and from what I have read on here that I should not backwash my filter until the pressure reads at least 8 psi more than it does after a fresh backwashing. My new gauge has not moved at all it was still reading 5 psi. I did try putting the old gauge back in and I got the same reading. Do you think that I may be dealing with a bad gauge or could I be dealing with some other problem?