Yippie: I read this on this site: " CYA - Cyanuric Acid - Protects chlorine from sunlight and determines the required FC level. (outdoors 30 to 50, SWG 70 to 80, indoors 0 to 20)" Since I have an indoor 5000Gal endless pool, which is covered 98% if the time, should I shoot for 20? The FC at 3.0 does not overpower me. I will probably add a little to see where it ends up. As an ER doc, I have learned it is easier to ad a little than to give to much......