Reverse Osmosis Systems

Rainsoft 21179 3-Stage RO Compatible Replacement Filters

The Rainsoft 21179 features a 1 micron carbon block prefilter, a 50 GPD TFC membrane, and another 1 micron carbon block for the post filter. The Rainsoft 21179 uses a carbon block pre-filter to reduce sediment, chlorine, and chlorine by-products before the membrane filters out impurities larger than .001 microns. The carbon block post filter treats for taste and odor. These filters are high-quality aftermarket RO filters that will produce outstanding drinking water. Note: If your Rainsoft reverse osmosis system is from 2013 or newer, it most likely is the Ultrefiner II. The Ultrefiner II requires proprietary filters that must be purchased from a Rainsoft dealer. Conversion kits to generic non-OEM replacement filters are available.

Replacement Filter Info

Sediment Filter (OMB934-5M - Rainsoft Part#: 9557 or 18557) - Replace every 6-12 months or as needed

RO Membrane TFC 50 GPD (TFC-RS9-50 - Rainsoft Part#: 9568, 18644, 18571, 12447, 21179, or 21176) – Replace every 24 months or as needed

Carbon Block Filter (OMB934-1M) – Replace every 6-12 months or as needed

Helpful Filter Information

Not all filters have the same replacement schedule. Replace the RO membrane filter every two years. Replace all other filters every 6-12 months. Help keep your system sanitary by never using filters longer than 12 months, except the RO membrane filter, regardless of how much water you use.

Filter Replacement Schedule

We’ve taken the guesswork out of replacing your filters. Begin a filter replacement cycle by replacing all filters on your system (Filter Kit "YSM"). The following year, or sooner if recommended by the manufacturer, replace all filters except the RO membrane (Filter Kit "YS"). Repeat this cycle by following the helpful diagram below.