I recently bought a 2800gpm intex sand filter, the filter works awesome and the water is night and day compared when running the cartridge filter that came with the pool. The problem I've been having is with the sand. I bought sand from home depot, the quickrete brand. I kept finding sand at the bottom of my pool for some reason (water was still crystal clear.) I emptied the sand and washed the filter as well as everything inside, went to leslies pool and got some silica from them. I noticed after I loaded the sand and backwashed I was still getting a lot of sand coming through the backwash hose. I turned it to rinse and backwashed again, less sand but decided to run the outgoing line through the old cartridge filter to try and eliminate sand from coming in. I am now getting a little sand in the pool, not as much as before but it's still there and the water is still clear. This is driving me crazy, I read somewhere in these forums someone recommend HTH brand but I cannot find it anywhere!