Contains sodium dichloroisocyanurate (SDIC) granules that contain 55% of available chlorine. Like TCCA, SDIC is a good choice for outdoor pools as it is not decomposed by UV radiation in sunlight and provides lasting effects in keeping the swimming pool free from microbes. SDIC dissociates into chlorine and cyanuric acid, where chlorine is either consumed or dissipated which would lead to a build up of cyanuric acid in pool water. Refilling the pool water periodically can reduce the cyanuric acid build-up. SDIC, unlike TCCA, has a neutral pH and will not affect the overall pH of the swimming pool.