so trying to get a little more filtration before i go but a duda bag. si i follow the directions here on adding de to sand fikter for a 1 psi raise. well 8 add 1/4 cup of de total and it eaised my filter pressure from 14.5 to 15.5. i then waited 24 hours and its still at 15.5 i even sweeped the pool to see if it would catch some of yhe dirt that was on thr bottom and its still at 15.5. the article said it will take atleadt a cups of de for a 1 psi raise. is this nornal for a 1/4 cup