... maxColour APHA (Hazen)40 max—Usage:HEDP is used as scale and corrosion inhibition in circulating cool ... metallurgy, fertilizer, etc.. In light woven industry, HEDP is used as detergent for metal and nonmetal. In ... , HEDP is used as chelating agent. The dosage of 1-10mg/L is preferred as scale inhibitor ... , 10-50mg/L as corrosion inhibitor, and 1000-2000mg/L as detergent. Usually, HEDP ...