I have had my pool for 8 going on 9 years and have had no issues. In the last 6 months, I have had green algae over and over and over. Leaves don't sit in my pool, I maintain my chemcials and I have shocked more in the last 6 months than since I've owned the pool. The pool store has no answers except for that my water is old so I should replace. I drained my pool, started over with new water - same problem. I purchased the TF-100 test kit hoping that would give me some answers. I've read through a lot of the info, but it starts to get overwhelming. Recommended levels are listed for Vinyl, Plaster or Fiberglass. I have Pebbletech ???????? These are my readings: FC-4 TC-5 pH-7.5 T/A-100 CH-600 CYA-85 If you can help I would be so grateful!!!!!!