Reverse Osmosis System Filters, RO Membranes and Parts

AllPure Water Filters ®

AllPure ® AP-4.0, AP-4.0/P, PT-4.0, PT-4.0/P Compatible Replacement Water Filters & TFC Reverse Osmosis Membranes - 4 Stage System

2 vertical filter housings, one top mounted horizontal inline GAC carbon post filter and one top mounted standard size horizontal RO membrane housing.

1st Filter is a 5 Micron Sediment Pre Filter. (Allpure SF-4001) - Replace Every 6 Months
2nd Filter is a Carbon Block Filter.  (Allpure CF-4000) - Replace Every 12 Months
3rd is the RO Membrane.  36 GPD TFC Replacement Reverse Osmosis Membrane. (Allpure MF-4009) - Replace As Needed (See How to Test)
4th Filter is an Inline Post Filter.  (Allpure 1F-4002) - Replace Every 12 Months

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Easy TDS Membrane Performence Calculator
See If It is Time To Replace Your Membrane

Simply enter your Feed Water TDS and RO Water TDS into the boxes above and click "Submit". The percentage of TDS Rejection will be displayed. We normally recommend membrane replacement once you drop below 75%. This may vary in areas with high TDS in the feed water.

See our selection of TDS meters under Water Tests


Be sure to check our Parts Department for important parts such as TDS Testers For Reverse Osmosis Membranes, Replacement Tanks, O-rings , Filter Housing Wrenches, Faucets, Pumps, Fittings, UV Systems and more parts for your reverse osmosis pure water filtration system.   View maintenance and servicing tips online at our Installation & Trouble shooting Guide.

* AllPure ® is the registered trademark of AllPure , the manufacturer of AllPure ® brand water treatment equipment.  The replacement filters and membranes listed above are not manufactured or endorsed by AllPure .  Rather, these filters and membranes are manufactured by other companies.  While these filters and membranes are compatible for use in AllPure ® brand water treatment equipment, we make no representation as to whether using these filters and membranes is consistent with the warranty and specifications applicable to AllPure ® equipment.