Please forgive me if this is readily available or obvious... somewhere I remember that the lower I keep my ph the more effective fc is in cleaning up (keeping ph at or above 7). When I clean up in the spring I try to keep at 7.2 and am astonished every time at how fast the filth clears up. I try to keep at 7.2 to 7.4 when swimming. No cya just keep dripping in bleach. Anyway I am trying to locate the ref on fc effectiveness at different ph levels...