I am new to this pool stuff after purchasing a house that has one. I replaced the old cartridge filter with a new Hayward sand system and it was suggested that I use Ruby Sand as the filter media. The pool was filthy with debris and algae which I have now conquered thanks to this site. SLAM!! The pool place totally failed me!! With all the stuff being filtered the pressure gauge has never moved from 18 psi even when backwashing was needed and return pressure low. I have talked to the Ruby Sand people, Waterway, and other pool places, but nobody has a clue about why this is happening. I have tried a new gauge which registered the same 18 psi as the original from Waterway so I ruled out the gauge, but Waterway is still sending me another one. I don't expect the gauge to change things. Every person in the business says I should not need to backwash unless the pressure rises 8 - 10 psi. Has anybody here experienced this kind of problem or heard of it so I have a clue as to what is going on to cause this??