Polyshield 400 is one of our remarkably cost effective RO antiscalant and Reverse Osmosis scale inhibitor which will inhibit a wide range of foulants including: calcium carbonate, calcium sulphate, barium sulphate, strontium sulphate, calcium fluoride, silica and iron.olyshield 400 is one of our remarkably cost effective RO antiscalant and Reverse Osmosis scale inhibitor which will inhibit a wide range of foulants including: calcium carbonate, calcium sulphate, barium sulphate, strontium sulphate, calcium fluoride, silica and iron.