Large selection of replacement water filters, reverse osmosis membranes, testing kits and water filter system repair parts. From one water filter or membrane to case quantity discounts.

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MCS Water Systems ®

MCS Water Systems ®

MCS ® Water Systems Model 4000 TCR 4 & 5 Stage TFC Reverse Osmosis System Replacement Water Filters & Membranes - MCS SuperTwist RO

3 vertical filter housings, one top mounted horizontal inline GAC TCR carbon filter. System needs a new top mounted standard size horizontal RO membrane housing when replacing the membrane. This is also a great time in increase the capacity of the system. See more on reverse osmosis membrane upgrading.


MCS ® Water Systems Model 4 Stage TFC Reverse Osmosis System Replacement Water Filters.

2 vertical filter housings, one top mounted horizontal inline GAC carbon post filter and a horizontally mounted membrane housing.

Replacement Reverse Osmosis RO Membrane

The Membrane Housing is the horizontal housing on top.  The 5 stage 4000 TCR system originally came with a Hydronautics 2012-LST-CPA2 membrane that is not industry standard configuration.  We suggest changing the membrane housing so that the system can use a standard style membrane.   

This is also a great time in increase the capacity of the system.  


MCS Super Twist Quick Change RO Reverse Osmosis System Replacement RO Membranes and Water Filters

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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.

* MCS ® is the registered trademark of MCS , the manufacturer of MCS ® brand water treatment equipment.  The replacement filters and membranes listed above are not manufactured or endorsed by MCS .  Rather, these filters and membranes are manufactured by other companies.  While these filters and membranes are compatible for use in MCS ® 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 MCS ® equipment.