It is a chemical compound added to swimming pool water to stabilize chlorine. It acts as a shield, protecting chlorine from degradation caused by ultraviolet (UV) rays from the sun. Without it, chlorine dissipates rapidly, rendering it ineffective at sanitizing the water and controlling algae and bacteria.
The presence of this compound significantly extends the lifespan of chlorine in outdoor pools. This stabilization effect reduces the amount of chlorine needed to maintain proper sanitation levels, leading to cost savings and a decrease in chlorine-related odors and irritation. Its introduction into pool chemistry revolutionized pool maintenance, allowing for more consistent and effective water treatment.