AntiChlor 30 liquid is a dechlorinating agent used as a mild, non-oxidizing biostat or injected into reverse osmosis (RO) feedwaters to protect polyamide membranes from permanent damage caused by chlorine. AntiChlor 30 is a 30% (minimum) solution of sodium bisulfite. It is a food-grade reducing agent and is certified by NSF International for use in systems producing drinking water.