Mechanism of oxidation by dichlorotriazenetrione
Dichlorotriazenetrione, also known as dichloroisocyanuric acid, is slowly hydrolyzed in water to isocyanuric acid and hypochlorous acid, which serves as the oxidation agent. The N-Cl bond is easily hydrolyzed because of its relative weakness, which is also reflected in the stability of nitrogen halides. The slow hydrolysis releases a low but constant amount of oxidizers. $\ce{HOCl}$ itself oxidizes organic compounds, being reduced to $\ce{HCl}$ in the process.



In aqueous solution, $\ce{HOCl}$ is in equilibrium with its anhydride $\ce{Cl2O}$ and elemental chlorine, which also serve as oxidizers. Furthermore, it slowly decomposes to $\ce{HCl}$ and oxygen, so that a mixture of different oxidation agents is present in its solution.

$$\ce{HCl + HOCl \rightleftharpoons Cl2 + H2O}$$

$$\ce{2HOCl \rightleftharpoons Cl2O + H2O}$$

$$\ce{2HOCl \rightarrow 2HCl + O2}$$