I am now at my wits end. I just can't figure it out. My filter has now been running 10 days and still will not clear water (blue and cloudy). (Filter and sand are 2 years old). Every few hours(6-7) my pressure goes way up, I do a backwash it comes back down and seems normal. If I try to vacumn I lose my pressure, and the gauge goes up. Went to the pool store and I got the response "Change your sand". Just doesn't add up to me, I need to understand what is going on. I also tried adding the 2 cups of DE and about 2 hours later up goes my guage and down goes my pressure. Any help would be greatly appreciated. Feel like the filter has turned into a roller coaster.