Closed loop cooling systems provide a unique set of environmental and microbiological conditions for
biocides to control microbial growth and fouling. Key factors for biocide selection include in-use
stability, solvent content, and materials compatibility. A new biocide product based on the
methylisothiazolone active ingredient was recently developed for use in closed loop cooling systems.
The new biocide is water-based, effective versus a range of bacteria, stable in high pH and high
temperature conditions, and contains no salts, metals, or organic solvents. Results of comparative
efficacy and stability studies versus commercial biocides will be presented.