When added to water, Sodium Dichloroisocyanurate Tablets dissolve to release a measured dose of Hypochlorous acid (Free Available Chlorine) that is universally recognized as a safe and effective water disinfectant. However, this unique water purification tablet, while chlorine based, will not colour the water or leave objectionable chemical tastes. http://www.zhaoguangroup.com/sodium-dichloroisocyanurate/