Chemical Agent Inhibitor T-601 Phosphonic acid, carboxylic acid copolymer is currently the most widely used one of polycarboxylic acid type water treatment chemicals can be used alone, but also with organic phosphonates and organic phosphate ester, poly-phosphate compound to use, better synergies can be in multiples of alkaline and high concentration without scale sediment used for power plants, steel mills, chemical plants, fertilizer plants, refineries and air conditioning systems, cooling water system to prevent them from scaling.