This is my second summer with my 24 feet AG pool. I have read here (and at many other places) that I should do a backwash when the pressure (indicated on the sand filter gauge) is 6 to 8 psi above 'normal' -- with 'normal being the pressure shortly after a backwash/rinse.
So, I decided to let the pressure going up and see how long it would take to let it go up 4 or 5 PSI. It has been 3 weeks and my pressure is still the same: the gauge has been indicating 16 for the last 3 weeks. Can it be that long? Should I backwash anyway or keep waiting until it gets to 21 PSI?