I'm a newbe. I'm still trying to figure out what I have, and how to close it, use it, mantain it ect.. The man that I bought the place from said, when the pool guy came to open up for him he said I,m going to add some different stuff to your sand. He belives it was DE. How do I find out whats in there? The filter has about fifty screws around it. Do I have to take them all off to look inside? Plus I'm kind of in limbo right now. My pool is half closed down. I'm converting from Eco-Smart to chlorine. I have my pool 4" below the eyballs, and the cover on. I haven't blown out the lines yet. I was going to have the local pool store do it, so i dont screw it up. Plus I could watch them and learn. The guy that owned before me left a shop vac that he wired to just blow and not suck. I have three eyeballs, one skimmer, and one sideport. Also when you use antifreeze doesn't that stuff get in the pool? Is that ok? The former owner told that he used to take the clear cover off the pump filter, then put the shop vac hose down in there about 6" and blow out from there. Sounds confusing. filix