Trichloro-s-triazinetrione is a dry solid containing the highest (90%) available chlorine content of any chlorine sanitizing pool treatment chemical except gaseous chlorine (100%).
This chemical is also known as trichloroisocyanuric acid or trichlor for short.
Trichloroisocyanuric acid is an EPA-registered pesticide sold for use as a sanitizer for pools and spas.
Trichlor is soluble in water, forming hypochlorous acid and hypochlorite ion or free available chlorine (FAC). Hypochlorous acid is more effective as a biocide than hypochlorite ion. The relative amounts of hypochlorous acid and hypochlorite will depend on pH.
Therefore, always maintain the pH between the recommended values of 7.2 and 7.8. The biocidal properties of trichlor are due principally to hypochlorous acid, which kills bacteria, algae, and other microorganisms. Because a residual level of FAC can be maintained with the use of trichlor, it is classified as a primary sanitizer. Trichlor is sold in tablet, stick and granular forms.