This paper discusses the development and application of a new alkaline cooling water treatment program that is completely halogen stable. Conventional alkaline treatments utilize phosphonate for calcium carbonate scale control and azole (tolyl triazole) for copper corrosion inhibition. Both of these materials are known to degrade in the presence of chlorine or bromine biocides, and with their degradation, a loss scale and/or corrosion control can occur. The new program utilizes new chemistry that is completely halogen stable and provides performance far superior to that obtained with the industry-standard phosphonate and azole (tolyl triazole). The halogen stable technology represents the first major advancement in cooling water technology in over 30 years. Along with laboratory data, two field case studies will be presented.