Reverse osmosis system
Rainsoft Ultrefiner II 3-Stage RO Conversion Kit Filters
Compatible parts
Everything that fits the Rainsoft Ultrefiner II
Replacement filter info
Your replacement schedule
Each stage of the Rainsoft Ultrefiner II, the exact part that fits it, and when to change it.
-
Kit: Filter kit, without membrane
Part YS-PURO4T75, Kit de filtro de reemplazo PuROTwist 4000T75 - Membrana se vende por separado $73.97
Every filter except the membrane
-
Kit: Filter kit, all stages
Every filter and the membrane in one box
Complete Rainsoft Ultrefiner II set
FAQ
Commonly Asked Questions about RainSoft Ultrefiner II RO Systems
Which replacement filters on this page fit the RainSoft Ultrefiner II?
The page includes Q-series sediment and carbon cartridges, a 75 GPD membrane with flow control, and 50 or 75 GPD conversion options. Match the installed manifold and the membrane rating before ordering.
Do PuROTwist filters connect directly to an unmodified RainSoft Ultrefiner II?
No. PuROTwist filters require the PT3000 or PT4000 conversion assembly shown on the page. Once converted, the existing faucet, storage tank, and serviceable tubing can generally remain while the manifold and filter format change.
What is the difference between a kit with a membrane and one without a membrane?
A complete kit includes the RO membrane along with the scheduled prefilters and postfilter. A no-membrane kit is for service intervals when the existing membrane is still performing properly. Read the package contents because individual cartridge counts vary by system.
How often should RainSoft Ultrefiner II filters be changed?
A common starting schedule is 6–12 months for sediment and carbon filters and about 24 months for the RO membrane. Feed-water quality, use, pressure, and measured membrane rejection can require earlier service.
How can I confirm that my system is really a RainSoft Ultrefiner II?
Check the model label on the manifold or cabinet and compare the installed cartridge style, tubing size, and membrane rating with the product page. Do not select a kit only because the faucet or tank looks similar.
Can I mix original-style filters with conversion-kit filters?
Not within the same manifold. Original-style cartridges attach to the original head; PuROTwist cartridges attach only after the corresponding conversion manifold is installed. After conversion, use the service kit specified for that converted configuration.
