Stringent environmental restrictions on chromate, and now on zinc, are forcing many plants to investigate alternative cooling water treatment technologies. A newly developed alkaline phosphate program operates in the same pH region as current alkaline zinc technologies. The alkaline phosphate program has broad calcium (80-1200 ppm as CaaCO3) and "M" alkalinity (100-350 ppm as CaCO3) application ranges. The new program provides excellent mild steel and yellow metal corrosion protection while maintaining clean heat transfer surfaces. Results from laboratory application testing and field performance evaluations will be presented.