FC was at 17 at 7:30 am. I added 3 qts. of bleach at that time since I knew I would be gone for a few hours. At 1:30 pm, FC was 15. I added another 3 qts. of bleach. At 4:30 pm, FC was 16. I was gone again for a few hours. I didn't add more bleach since it was 4:30 in the afternoon. Got home and checked FC again at 8:30 pm, and it was 13.5. I lost 2.5 ppm between 4:30 and 8:30 in the late afternoon/evening. Seems like a lot. I've added another 3 qts of bleach now (at 8:30 pm). That seemed the way to go rather than worrying about chlorine loss. Is this loss excessive for time of day? Sun sets about 7:30 pm and it's hot (mid 80's) but sun is off the pool by 5:30 pm or so. So, is the loss due to sunlight? Does stubborn, refuse-to-die algae exist???? I feel like I have been shocking for ages.
Thanks.