Ok, I opened pool and it was green this year. So I changed sand in filter and did the SLAM to clear pool. It took about 8 days. It passed the over night test, water was clear, and CC was 0. Now water is still crystal clear. The problem I am having is when I clean pool the next day or so I start to see what looks like dirt on bottom of pool. When I brush pool it looks like it just poofs up and disappears. I brush pool, and vacuum bottom, but it comes back. I am at wits end trying to get rid of this dirt or algae. Any help would be appreciated.