Corrosion control is a critical factor in the maintenance of low hardness, or soft industrial cooling water systems. Soft water corrosion problems are increasing due to the use of non-chemical pretreatment systems, e.g., desalination and reverse osmosis. Using process simulation and electrochemical data. This paper describes the use of currently available chemical technology as a possible solution to this problem comprising phosphonate chemistry have been optimized for minimum corrosion rates in representative test waters.