Just for full disclosure, we got our pool used. It was put up new for 2010 season, but HOA made the original owner take it down. They used it for that season while appealing, etc just to be able to use it. I don't know if it was taken down in the fall or spring of 2011. I got it last summer and everything sat till this spring. After I had everything hooked up, the first thing I did was backwash for several minutes. The pressure gauge was broken so I replaced it. The new gauge has the water pressure at 17 PSI consistently since I put it in. Last weekend vacuuming a lot of **** after 2 storms, the pressure didn't really go up, I expected it to. After vacuuming again and backwashing yesterday, the pressure still neither rose nor fell. Is it just I have a really clean pool? Or maybe I am not backwashing/rinsing well enough? How much of a change in pressure should I expect before having to backwash?