For the past 2 years, the normal operating pressure of our DE Filter is 20. After opening the pool a few days ago, it stabilized at 20. Since this morning, i've been backwashing every hour or so because the pressure gets to 25. But I just noticed that, even after backwash/rinse/backwash, the pressure is still at 25. The water coming out of waste is almost clear.. and when i start it up again, it goes to 25 still. I checked all the skimmers and the filter basket.. what am i missing? fyi, at this point, there is almost no DE in the filter now that i've been backwashing/rinsing so much just to see if the pressure would go down.