Cyanuric acid is a chemical compound added to swimming pool water. Its primary function is to protect chlorine from degradation caused by ultraviolet (UV) rays from the sun. Without this protection, chlorine dissipates rapidly, rendering it ineffective as a sanitizer. For example, in direct sunlight, unstabilized chlorine can lose up to 75% of its effectiveness in just a few hours.
The presence of cyanuric acid significantly extends the lifespan of chlorine in pool water, reducing the need for frequent chlorine additions. This results in cost savings for pool owners and helps maintain consistent sanitation levels, which are essential for preventing the growth of bacteria and algae. Historically, issues with chlorine loss in outdoor pools led to the widespread adoption of cyanuric acid as a standard component of pool maintenance.