Compatible Reverse Osmosis Membrane Filter that will fit in the Rainsoft RO System # 21176 Reverse Osmosis System

- The Membrane, Not The Prefilters A Thin Film Composite Reverse Osmosis Element For Rainsoft Systems Using The 21176, 21179 And 21191 Cartridges. This Is The Stage That Strips Dissolved Solids From The Water. Carbon Prefilters Are Sold Separately And Run On A Shorter Interval.
- Chlorine Is What Kills A Membrane Thin Film Composite Is Destroyed By Chlorine, Which Is Why The Carbon Stage Ahead Of It Matters More Than Any Other Cartridge In The System. A Neglected Carbon Prefilter Will Cost You The Membrane Long Before Its Own Life Is Up. Keep The Carbon On Schedule And This Element Runs About A Year, Longer On Soft Municipal Water.
- How To Tell It Is Done A Membrane Does Not Clog The Way A Sediment Cartridge Does. It Fails Gradually, And The Signs Are Slower Tank Recovery And Water That No Longer Tastes As Clean As It Did. If You Own A Tds Meter, Rising Readings At The Faucet Are The Clearest Signal. Falling Flow With Normal Taste Is Usually A Loaded Prefilter Instead.
- Compatible Replacement, Not An Original Manufacturer Part Cfs Is An Independent Brand. This Is A Compatible Replacement, Not An Original Manufacturer Part, And Manufacturer Names And Part Numbers Are Used For Reference Only To Show What It Fits: 21176, 21179, 21191.
- Fitting And First Use The Element Pushes Into The Vessel O-Ring End First And Must Seat Fully, Or Feed Water Will Bypass It. Let The Tank Fill And Drain Completely Once Or Twice Before Drinking, Which Flushes The Preservative The Membrane Ships In. Cloudiness On The First Fill Is Dissolved Air, Not A Fault.