In March of this year we had our first pool installed (18'x54" AGP). I have been on TFPC since installation and have been very happy. In late June or early July my water temp was consistently above 90 degrees and we had a low level algae bloom with CYA at 30 ppm and targeting 4 ppm FC. After a slam, I followed the advice of others on this site and increased to CYA of 40 ppm and targeted FC of 8 ppm with a minimum of 4 ppm. No problems, but I did have to go to 8.5 ppm FC every night to maintain a minimum of 4ppm FC because I get 12 to 13 hours of sun per day.
This week, we had a small amount of green algae in the areas of the pool that has slower flow when the pump is on. I'm running the pump 9 hours per day on high and have a cartridge filter. The filter is clean. The kids have only been swimming about once per week because of school and extra curricula activities. I try to brush once per week, but got behind on it. I slammed and after two days I passed all criteria and was done. Today, I went to the pool store to kill time and they nearly dropped dead when I told them that my FC is brought up to 8.5 every night to maintain a minimum of 4. They suggested raising the CYA to 80 and getting back down to an FC of 3 or 4 ppm. I talked to a friend of mine who maintains pools and he was less concerned. He did feel that I should bring the CYA to 50 or 60 and so my FC will not swing so wildly. He feels that I should be targeting and FC of 5ppm and a minimum of 3 or 4 ppm.
I'm usually adding 46 ounces of 8.25% bleach per night. I'm spending about $6 per week on bleach. Had to SLAM twice from March of this year to now. Am I adding to much chlorine and is my CYA too low?