Comparative studies were made on the bactericidal effect of hypochlorite, hypochlorite and isocyanurate, and chloramines. Survival of Escherichia coli exposed to hypochlorite for about 15 sec was not affected by the addition of 30 ppm of isocyanurate. In contrast, chloramines required 4-6 times of available chlorine concentration to obtain the same effect as that of hypochlorite, or 3-5 times longer exposure with the same concentration of chlorine.
