What is one advantage of using cyanuric acid in pools?

Using cyanuric acid in pools primarily serves the purpose of stabilizing residual chlorine, which is the reason it is the correct answer. Chlorine is a vital chemical used to sanitize pool water, but it can be easily broken down by ultraviolet (UV) rays from sunlight. When cyanuric acid is present in the water, it forms a protective compound with chlorine, reducing the rate at which chlorine is lost to UV exposure. As a result, this stabilization allows chlorine levels to remain effective for a longer period, ensuring better water quality and reducing the need for frequent chlorination.

This property of cyanuric acid means that pool operators can maintain effective disinfection with lower levels of chlorine, which also enhances swimmer safety and reduces chemical costs in the long run. Thus, the use of cyanuric acid is essential in outdoor pools where sunlight exposure is significant.