Believe it or not I went and picked up some DE today because my pool has been cloudy since opening it up a couple weeks ago. I read this post today and figured I'd give it a shot. Unfortunately I picked up a 25lbs bag at home depot today, not realizing it only called for 1/3 cup. Anyways, I added the 1/3 cup a few hours ago and did not notice any of it coming out of the returns and my PSI did raise 1 PSI as described in that post.