hello all. first time poster. 5 year pool owner. normally, my pool's filter (a leslie's crystal clear II DE filter) will run in the 15-22psi range. when it gets above that, i'll backwash and add the DE. in the last couple of days though, i've run into a potentially serious problem. when running the pool vacuum, the pressure got up to almost 35psi (it's never gotten above 15 before). i turned it off and took out the vacuum. i ran the filter like normal, and it still ran very high. i did a backwash hoping that would work (we had a ton of rain in SoCal recently, and the water level was high). this helped for maybe an hour, and then the pressure went from about 15 back to 35psi. something else that has been happening is that the filter sounds like it's ramping itself up. it'll be at 30psi, and then rev up to 35 for a few seconds, then rev down to the high 20's, and then back up to about 35, but not staying on a constant pressure. i made sure the baskets were cleared and there were no blockages. i haven't been able to check the main pool drain as it's about 8 1/2 feet down, and i'm planning on cleaning the inside of the main filter (i do this 3-4 times a year). has anyone else had this experience or heard about something like this? i'd like to avoid bringing in a professional and spending big money.