Cyanuric Acid in Pools: What It Does and How Much You Actually Need
Cyanuric acid (CYA) acts as sunscreen for your pool chlorine, slowing how fast UV rays burn it off. Without it, outdoor pools can lose most of their chlorine within a few hours of direct sun. But too much CYA is just as much of a problem — it weakens chlorine's ability to sanitize, and the only fix is a partial drain.