What is the purpose of cyanuric acid in pool water?

Cyanuric acid plays a crucial role in outdoor swimming pools, particularly in maintaining effective levels of chlorine. When chlorine is added to pool water, it is highly susceptible to degradation due to ultraviolet (UV) rays from the sun. This results in the rapid loss of chlorine, which can lead to inadequate sanitation and water quality issues. By adding cyanuric acid, it acts as a stabilizer for the chlorine, effectively allowing it to remain active longer in the presence of sunlight. This stabilization helps ensure that the residual chlorine levels are adequate to maintain clean and safe swimming conditions.

The other options do not accurately reflect the primary function of cyanuric acid. While reducing total dissolved solids (TDS) and preventing pH fluctuations are important for overall water chemistry, they are not specific functions of cyanuric acid. Additionally, using cyanuric acid to scrub pool tiles falls outside its intended purpose and function in pool maintenance.