One of the most critical categories of cooling tower chemicals is biocides. Cooling towers, if left untreated, can become breeding grounds for bacteria, algae, and other microorganisms. The presence of these organisms can lead to corrosion, scaling, and biofilm formation, all of which can negatively impact system efficiency. Biocides, such as chlorine, bromine, and newer non-oxidizing agents, are employed to control microbial growth. They are usually added on a regular schedule or as part of a shock treatment to eliminate existing contaminants, thereby enhancing the overall health of the cooling system.