A broad-spectrum, non- oxidizing biocide approved for use in recirculating cooling towers, closed loop cooling systems, air washers and brewery pasteurizers. It is US EPA registered liquid microbiocide used to control bacteria, fungi, and algae. It contains a mixture of isothiazoline compounds and is registered for use in a range of water treatment applications including recirculating cooling and process water systems, air washers, and non-potable reverse osmosis systems.