I am currently doing a slam. I thought my CYA was slightly over 100 but doing a dilution test I recently found my CYA was 210... I was not keeping my FC high enough and started getting a bit of algae. I drained a ton of water... refilled and then drained more... I am now down to CYA of 85 so I figured I would start my SLAM with this much more manageable CYA level. Tonight (after dark) a brought my FC up to 40 and then 2 hours later I tested it and it was down to 31 but I still only had .5 CC. If so much FC is being used to kill organics how is my CC still so low?