The Dolphin is supposed to filter down pretty small, and it did pick up a lot of stuff. What's happening now is that I've run the Dolphin twice but still have sand/silt/dirt all over the floor of my pool. It seems to pick up stuff but then things either settle back to the bottom or is being blown back in through the return. I figured out today that my spider gasket needs replacing, and I have one ordered. I'm starting to think that what I'm seeing on the bottom is sand, possibly from the filter. I have a PF-50 filter and just did a sand replacement last year. I took the whole thing apart and checked/cleaned/replaced laterals and visually checked everything inside. It all looked good besides the two cracked laterals that I replaced. I added 200# of sand that I got from the pool store. It worked good for the rest of the season last year. Will the spider gasket have anything to do with sand on the floor? I'm assuming that since I just checked and replaced laterals last year that they should be fine. What else would cause the sand from my filter to end up in my pool?