Trichloroisocyanuric 90% (TCCA) Acid contains about 90% active chlorine. Except for actual chlorine gas, it is the most concentrated form of chlorine on the market.

It is also a form of "stabilized" chlorine. It is made with cyanuric acid (CYA) for added protection against the sun and UV rays.

Because of its acidic composition, it has a very low pH level of about 3. Basically, using trichlor pucks will lower both pH and total alkalinity (TA) levels, and increase CYA over time. Keep that in mind, and always test your water to ensure your levels are balanced!