in reverse osmosis water purification system is disclosed the method uses a composition composed of low molecular weight polyacrylic and phytic acid in a synergistic combination and significantly reduces build up of calcium magnesium and or iron scale application_number US 46786783 A description as discussed above in practicing the present invention the infeed water to the purification system should contain from 0 01 to 20 ppm of a low molecular weight polyacrylic acid and from 0 01 to 20 ppm of phytic acid considering the solubities of these ingredients and the necessity for operation of a reverse osmosis water purification system in the field under often rigorous conditions and with equipment of relatively low precision it is not practicable to inject the polyacrylic acid and phytic acid directly into the infeed water without diluting them first on the other hand it is uneconomical to ship the concentrate in a diluted or semi diluted form simply because shipping costs are based on weight and it is expensive to ship water the composition is therefore most efficiently manufactured and shipped in a concentrated liquid form and diluted in the field to form a stock solution which is in turn injected into the infeed water stream to achieve the final dilution it is pointed out incidentally that the ingredients of this composition are both biodegradable and environmentally safe the low molecular weight polyacrylic acid used by us is commercially sold as 34 syntergent jf 34 by diamond shamrock syntergent jf is a syrupy liquid consisting of a solution of polyacrylic acid having a molecular weight of from 1 000 to 2 000 in water the solution being approximately 50 by.