I don't know what the directions on your bag of Fiber Clear say, but some of the bags say to add x-number of pounds. Other bags say to add x-number of scoops and even have a little scoop (cup) in the bag. Anyway if you have one that says pounds, that refers to the old standard of measuring DE with the volume of a 1 pound coffee can. You do not want to put in pounds by weight! Pool stores sell DE scoops that hold the volume of the now obsolete 1 pound can. I don't know if this is your issue or not, but I thought I would pass it along.