CYA's Relationship to Chlorine


Well-known member
Apr 26, 2015
Leesburg, GA
Can someone explain how CYA impacts the effectiveness of chlorine? I understand that CYA helps preserve/protect chlorine from sunlight. How does that work? Does it combine with and protect chlorine, keeping chlorine from working as a sanitizer below a certain level, depending on the level of the CYA? In other words do you have to have a chlorine level above and beyond a certain point, depending on the CYA level in order for the chlorine to work as a sanitizer?


Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV

The above link takes you to our science thread. It gets pretty deep.

Your last sentence is correct. You have to maintain a certain ration of FC to CYA so that a sufficient amount of FC is available to sanitize.