Some folks have had better success by installing it AFTER the pre-filters and just before the water goes into the membrane

or multiple points in an RO system

Reverse Osmosis Pressure Reducing Valve: PSI

Equipped with a Flow Restrictor

Stainless steel 150 psi pressure gauge with bottom mount 1/4" in-line quick connect fitting included

Aries® 10" × 2½" Heavy Metals Removal Cartridge ICEMAKERCONNECTIONKIT Some folks have had betterAries 10" 2" Heavy Metals Removal Cartridge Aries 10" 2" Heavy Metals Removal Cartridge . Using premium Resintech media and offering oversized cartridge cavities, AF Series cartridges provide the best in water purification and filtration. Standard Features Aries 10" 2" Heavy Metals Removal Cartridge Scale, Taste & Odor Cartridges Aries FilterWorks offers a propriety blend of a high capacity weak acid ion exchange resin to reduce calcium and magnesium