Cyanuric acid, often abbreviated as CYA, is a chemical compound used in swimming pools to stabilize chlorine. It acts as a protectant, shielding chlorine from degradation caused by ultraviolet (UV) rays from the sun. Without it, chlorine dissipates rapidly, rendering it ineffective at sanitizing the water. A common example is the addition of stabilized chlorine products, such as dichlor or trichlor, which contain CYA.
Maintaining an appropriate level is crucial for effective pool sanitation and water quality. Too little allows chlorine to be consumed rapidly, resulting in the need for frequent additions and potential algae growth. Conversely, excessively high levels can reduce chlorine’s efficacy, leading to cloudy water, algae blooms, and eye irritation. Historically, its use has become commonplace as pool owners sought to prolong the sanitizing effects of chlorine.