The system should be filled with good quality fresh or distilled water and where freeze protection is necessary, the proper amount of glycol-based antifreeze should be added. Begin circulating the system water, and add RXSOL-40-4021 cooling water treatment at an initial dosage of 8 liters per ton of system water capacity. Circulate for 30 minutes after addition to ensure good distribution and the establishment of a protective film. RXSOL-40-4021 cooling water treatment may be used with waters that have hardness contamination, provided the total hardness levels are less than 170 ppm or as otherwise recommended by the engine manufacturer, whichever is less. The chloride level in the cooling system should be limited to 100 ppm or as otherwise recommended by the engine manufacturer, whichever is less.