I haven't seen any evidence of algae blooms. I've been using more chlorine that usual, but have had more people in the pool too. Yesterday, the pool was 3ppm. Via the pool store, the CYA was 10 on Sunday. I couldn't get it to register on the taylor test. We added enough to bring it to 25, as that's all the CYA we had. Via pool math's calculations 16oz would bring it to 25, but it's now 40ish. I assume this fact that the CYA was higher than I thought it was, caused the problem with FC being too low. I didn't want to retest the CYA until it had been in for 2 days to give it time to come up. However, the minimum for cya of 40 is 3, so why did I have a problem to begin with?
A few hours ago, I tested FC and the it was 0 with CC at .5 (it's rare I get a 0 reading, it's usually .5). So, I added 1/2 gal and tested again in 2 hours and it was only 2ppm and water is a tiny bit cloudy. I've added the remainder of the gallon and I'll retest in an hour.
So, I know this is likely the beginning of algae, but without blooms or anything green, do I need to start a SLAM or just maintain the levels I should have for a CYA of 40?