Okay after 5 days of shocking yesterday I brought the level up to 30ppm to try to get this issue resolved. I had been maintaining it most of the day then at about 6:00 I raised it to 30ppm again. It held. I check it at midnight and it was 29ppm with 0 CC.
I woke up this morning and checked it at 9:00 and it was 20ppm, so a loss of 9ppm, BUT the pool already has gotten 3 hours of sunlight.
1) When Chlorine levels are higher does the sun eat it away faster? Basically can I assume that the 9ppm loss overnight was just from the 3 hours of direct sun this morning?
2) Am I done shocking?
Pool is clear and has been since I started
CC is .5 or less
Chlorine held for at least 6 hours at night, maybe more.