Stabilizer, composed mainly of cyanuric or isocyanuric acid, plays a key role in disinfecting pool water exposed to sunlight. UV rays rapidly degrade free active chlorine, reducing its effectiveness within a few hours. The stabilizer acts by chemically binding to the chlorine, forming a protective barrier that slows down its degradation. Once bound, the chlorine is released progressively into the water, providing continuous, longer-lasting disinfection, even in direct sunlight.

Although stabilizer is very useful, excessive use can be problematic. When the concentration of cyanuric acid exceeds 50-70 ppm, it can reduce the effectiveness of active chlorine. Excessive stabilizer “blocks” chlorine, making it less available to fight bacteria and algae. This is known as “blocked chlorine”. This can lead to water imbalances and quality problems, such as cloudy water or algae.

The ideal concentration of stabilizer in a swimming pool is between 20 and 50 ppm. Regular water testing is essential to avoid overdosing. If the concentration becomes too high, part of the pool water will need to be renewed to restore the balance.

To sum up: Stabilizers are an invaluable ally in protecting chlorine from UV rays and maintaining effective disinfection. However, moderate use and rigorous monitoring are essential to prevent it from compromising water quality.