Do I need to address the other numbers? Calcium? Hardness? Etc.…You have to be able to see the bottom for swimmer safety in case somebody was drowning. It would be rare but things could turn tragic in 5 minutes or less. As long as you can see the bottom you can swim at up to and including SLAM level of the FC/CYA Levels
Couldn’t do it without you and a few others on this forum.