Replacement water filters, RO reverse osmosis membranes and whole house filter systems. Refrigerator water filters, pool and spa filter. Pentek, OMNIFILTER water filters. Chiller Daddy water chillers

Search
Cart ()
Order Tracking
Reorder
Toggle Nav
Home
Replacement Water Filters
Reverse Osmosis Systems
Whole House Water Filters
Refrigerator Water Filters
Water Testing
Pool and Spa Filters
Boat & RV Water Filters
Parts Department
Water Chillers
Installation and Trouble Shooting Guide
Specialty Water Filters
Well Water
Gift Guide
Toggle Nav
Cart ()
Order Tracking
Search
Advanced Search
Menu
Menu
Account

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.

LOW PRICES and FAST SHIPPING SINCE 1999 !

99.5% Of All Items In Stock For Same Day Shipping!

4 Stage TFC Inline Reverse Osmosis RO Pure Water System Help

4 Stage TFC Inline Reverse Osmosis RO Pure Water System Help

4 Stage TFC Reverse Osmosis System With Inline Post Filter Replacement Water Filters & Membranes

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

  1. GE Osmonics ® Purtrex PX-5-978 Sediment Replacement Water Filter # 93023
    GE Osmonics ® Purtrex PX-5-978 Sediment Water Filter # 93023
    GE Osmonics ® Purtrex PX-5-978 5 Micron Sediment Water Pre Filter. True-graded density pure polypropylene depth replacement water filter. # 93023 9 7/8" long X 2 1/2" diameter. 40 per case, sold individually. Order a case and save even more. Learn More
    $8.99 Special Price $5.99 As low as $3.99
    Add to Wish List Add to Compare
  2. GGN-10-2-1000
    GGN-10-2-Block Premium Quality Carbon Block Replacement Water Filter
    10 Micron Premium Carbon Block Filter. Replaces KX Carbon Block Water Filter # 10-250-190-975 Compatible Replacement. The perfect carbon block for your standard reverse osmosis system. Extruded Carbon Block Water Filter. 9 3/4" long X 2 1/2" diameter OD X 1 1/4" diameter ID. 20 per case, sold individually. Order a case and save even more. GGN-10-2-BLOCK Learn More
    $12.99 Special Price $9.99 As low as $7.79
    Add to Wish List Add to Compare
  3. Omnipure CL-10RO-T/33 GAC Inline Replacement Water Filter-1000
    Omnipure ® CL-10RO-T/33 GAC Inline Water Filter
    Omnipure ® CL-10RO-T/33 GAC - 10" X 2" Carbon Inline Replacement Post Water Filter - GAC (granular activated carbon) Acid Washed Carbon - Should be changed at least every 12 months. 25 per case, sold individually. Order a case and save even more. Learn More
    $21.99 Special Price $11.99 As low as $9.49
    Add to Wish List Add to Compare
  4. 4 STAGE- Standard Filter Change Kit -2000
    4 Stage Standard Filter Change Kit - Grp

    4 Stage Reverse Osmosis Filter Change Kit. Standard size replacement RO water filter cartridges for a standard 4 stage RO drinking water system.

    • (2) 5 Micron Sediment Pre Filters   (change at least every 6 months)

    • (1) 10 Micron Carbon Block Pre Filter   (change at least every 12 months)

    • (1) GAC Inline Post Filter   (change at least every 12 months)

    Learn More

    Starting at $5.99

    Add to Wish List Add to Compare
  5. DESAL - TFM-18 RO Reverse Osmosis Membrane #1220188 GE Osmonics -1000
    Desal ® TFM-18/T112-18 RO reverse osmosis membrane # 1220188 GE Osmonics
    Desal ® TFM-18 GE Osmonics - 18 GPD (gallons per day) TFC Style reverse osmosis membrane - Fits Standard Size Membrane Housing. # 1220188. Pentair ® / GE Osmonics ® 18 GPD Thin Film Reverse Osmosis Membrane Model # TFM-18 - Part # 1220188. THE DESAL TFM-18 HAS BEEN DISCONTINUED AND IS NO LONGER AVAILABLE. IF YOU ORDER THE DESAL TFM-18 YOU WILL RECEIVE THE T112-18. Learn More
    $89.99 Special Price $49.99 As low as $39.99
    Add to Wish List Add to Compare
  6. DOW FILMTEC TW30-1812-24 RO #93430 Reverse Osmosis Membrane- 1000
    Dow Filmtec ® TW30-1812-24 RO reverse osmosis membrane # 93430

    Dow Filmtec ® TW30-1812-24 24 GPD TFC RO reverse osmosis membrane - standard size 1.75" X 11.75" Part # 93430

    Learn More
    $89.99 Special Price $56.99 As low as $37.99
    Add to Wish List Add to Compare
  7. DOW FILMTEC - TW30-1812-36 #80719 RO Reverse Osmosis Membrane-1000
    Dow Filmtec ® TW30-1812-36 RO reverse osmosis membrane # 80719
    Dow Filmtec ® TW30-1812-36 TFC 36 GPD RO reverse osmosis membrane - standard size 1.75" X 11.75" Part # 80719 Learn More
    $99.99 Special Price $59.99 As low as $39.99
    Add to Wish List Add to Compare
  8. DOW FILMTEC - TW30-1812-50 RO Reverse Osmosis Membrane #80722-1000
    Dow Filmtec ® TW30-1812-50 RO reverse osmosis membrane # 80722
    Dow Filmtec ® TW30-1812-50 TFC 50 GPD RO reverse osmosis membrane - standard size 1.75" X 11.75" Part # 80722 Learn How To Upgrade Your Reverse Osmosis Membrane Capacity Learn More
    $84.99 Special Price $69.99 As low as $54.99
    Add to Wish List Add to Compare
  9. DOW FILMTEC TW30-1812-75 (BW60-1812-75) #114731 RO Reverse Osmosis Membrane- 1000
    Dow Filmtec ® TW30-1812-75 (BW60-1812-75) RO reverse osmosis membrane # 114731
    Dow Filmtec ® TW30-1812-75 (BW60-1812-75) TFC 75 GPD RO reverse osmosis membrane - standard size 1.75" X 11.75" Part # 114731 Learn More
    $119.99 Special Price $74.99 As low as $49.99
    Add to Wish List Add to Compare
  10. DOW FILMTEC - TW30-1812-100 HR RO Reverse Osmosis Membrane 170102- 1000
    Dow Filmtec ® TW30-1812-100 HR RO reverse osmosis membrane
    Dow Filmtec ® TFC 100 GPD RO reverse osmosis membrane - standard size 1.75" X 11.75" Extra fast recovery and high production flow rate.

    Learn How To Upgrade Your Reverse Osmosis Membrane Capacity

    Learn More
    $129.99 Special Price $84.99 As low as $59.99
    Add to Wish List Add to Compare
  11. Flow_Restrictor-1000
    Inline reverse osmosis membrane flow restrictor
    Premium inline reverse osmosis membrane flow restrictor - Our in-line capillary flow restrictors are simple to install. Simply push the 1/4" poly tube firmly into the quick connectors and you are done. Be sure that you order the flow restrictor size to match your reverse osmosis membrane size. Arrow on side points toward the drain. Very simple to install. Learn More
    $33.99 Special Price $19.99 As low as $14.99
    Add to Wish List Add to Compare
  12. Pro Products Sani System Sanitizer
    Pro Products Sani System Sanitizer
    Pro Products Sani System Sanitizer. 0.25 or 0.5 fl. oz. concentrate. Sani-System ® Pro Products is proud to introduce Sani-System, the first and only EPA product approved for sanitizing water softeners, RO units and Water Coolers. Sani System is proven to kill 99.9% of E. coli, E. coli O157:H7, Staphylococcus aureus, Listeria monocytogenes and other harmful bacteria. It does not use chlorine, other oxidizers or acids that can harm water softener equipment parts. Use is simple; each dose comes in a pre-measured pouch. Just cut, pour and regenerate softener. No measuring, No mess! Sanitizing Equipment! Applications Interior Surfaces of Water Softeners, Reverse Osmosis (RO) Units, Ice Machines, Water Coolers, Water Holding Tanks and Pressure Tanks. Sani-System is now NSF certified! This is the best sanitizing solution available anywhere! Stock up and save. Learn More
    $7.99 Special Price $4.99 As low as $2.49
    Add to Wish List Add to Compare
  13. Molykote-From DOw Corning- 111 Compound-6 Gram O-ring Silicone Lubricant & Sealant-Dow-111-5-gram-1000
    Dow Corning (Molykote) ® 111 6 gram O-ring Silicone Lubricant and Sealant - Be sure to lube your O-rings to help prevent leaks.
    Dow Corning/Molykote ® 111 6 gram O-ring Silicone Lubricant and Sealant - 6 gram pillow pack. (like a ketchup packet) Great O-ring sealant and lubricant. FDA and NSF approved. (Do Not Use Petroleum Jelly As It May Break Down O-rings Or Housings) This is the same premium grade silicone sealant and lubricant used in underwater photography cameras, scuba gear and other underwater applications that simply can't afford leaks. Why not use the best for your reverse osmosis or drinking water filtration system?

    Dow 111 Silicone MSDS Safety Sheet

    Learn More
    $5.99 Special Price $3.99 As low as $1.79
    Add to Wish List Add to Compare
  14. TDS Meter - Test For Total Dissolved Solids In Water - Reverse Osmosis Membrane Tester - TDS Meter
    TDS Meter - Test For Total Dissolved Solids In Water - Reverse Osmosis Membrane Tester - TDS Meter
    TDS Meter - Tester. The Only Way To Know If Your Reverse Osmosis RO Membrane Is Performing Correctly - Tests for TDS - Total Dissolved Solids. A Must For All RO System Owners. Compare Incoming Feed Water To Treated Water - Replace Membrane If Less Than 80% of TDS Is Being Removed - The lower the TDS level in the water, the more efficiently your body's cells actually get hydrated by the water that you drink. The higher the TDS levels in the water, the greater the probability of harmful contaminants that can pose health risks or hinder the absorption of water molecules on the cellular level. Simple to use for Reverse Osmosis membrane monitoring. We really like this tester and think that anyone who wants to know about the quality of their water should have one of these TDS Meter Testers to monitor their RO membrane. Learn More
    $49.99 Special Price $37.99 As low as $17.99
    Add to Wish List Add to Compare
  15. TDS Meter Inline Water Tester DM1 - HM Digital Dual Mode Reading
    TDS Meter Inline Tester- Dual Mode Reading - Easily Installs Inline - Very Simple To Use
    TDS Meter - Dual Mode - Installs Inline - Check the TDS level with the push of a button. Now you can easily check to make sure the water from your reverse osmosis system is top quality. Measure the tap water coming in vs. the purified water going out of your system at any time. Very easy installation. FEATURES Displays TDS levels of the feed water and product water with in & out electrode probes. Highly efficient and accurate due to its advanced microprocessor technology. Auto-Off function conserves battery power. The unit shuts off automatically after 10 minutes of non-use. Comes equipped with John Guest Quick-Connect T-fittings as shown. Installs quickly and easily. SPECIFICATIONS Range: 0-9990 ppm Accuracy: ±2% Always know if your RO membrane is performing correctly! Learn More
    $49.99 Special Price $39.99 As low as $19.99
    Add to Wish List Add to Compare
  16. GGN-Faucet-AG-P-Chrome Air Gap Faucet-Long Reach-1000
    Chrome Air Gap Faucet - Long Reach GGN-FAUCET-AG-P

    LONG REACH, AIR GAP FAUCET IN CHROME

    Learn More
    $39.99 Special Price $29.99
    Add to Wish List Add to Compare
  17. 4 Gallon Reverse Osmosis Tank GGN-Tank-4-Pro 3.2
    4 Gallon Reverse Osmosis Tank GGN-Tank-4-Pro 3.2

    4 Gallon Reverse Osmosis Tank GGN-Tank-4 Pro 3.2

    Learn More
    $79.99 Special Price $49.99
    Add to Wish List Add to Compare
  18. Air Pressure Gauge for Reverse Osmosis Water Accumulator Tanks -1000
    Air pressure gauge for reverse osmosis water accumulator tanks
    Air pressure gauge for reverse osmosis water accumulator tanks - Specially calibrated for reverse osmosis system tanks. Scale from 1 to 20 PSI. Large scale reading over small PSI range allows optimum accuracy. Just like car tires lose air pressure, so does the bladder of your reverse osmosis water accumulator tank. Improper tank air pressure will cause your system to operate improperly. This is a must for all reverse osmosis system owners. Learn More
    $24.99 Special Price $17.99 As low as $12.99
    Add to Wish List Add to Compare
  19. Inversion Tank Stand Reverse Osmosis System
    Inversion Tank Stand Reverse Osmosis System

    Inversion Stand for Water Tank on  Reverse Osmosis Systems

    Learn More
    $27.99 Special Price $17.99
    Add to Wish List Add to Compare
Learn to increase the GPD capacity size of your reverse osmosis membrane
Learn to increase the GPD ...

Learn how to increase the GPD capacity of a Reverse Osmosis membrane. Upgrade made easy. Low prices and fast shipping online since 1999. Millions sold.

More
RO Membrane Trouble
RO Membrane Trouble

RO Reverse Osmosis Membrane Trouble Shooting Tips Online at WaterFiltersOnline.com

More
Parts Department
Parts Department

Replacement water faucets, water pumps, tanks, UV, drain saddles, o-rings, wrenches, valves, water accumulator tanks, fittings, TDS meters, water filters, reverse osmosis membrane sparts for reverse osmosis and pure water drinking systems. Buy online.

More
Installation and Trouble Shooting Guide
Installation and Trouble ...

Water Filter System and Reverse Osmosis System Installation and Service Guide. Huge inventory of replacement water filters , reverse osmosis membranes and maintenance service parts. Low prices and fast shipping online since 1999. Millions sold.

More
Flow Restrictors
Flow Restrictors

Flow Restrictors and Flow Controls For Reverse Osmosis Drinking Water Systems

More
Membrane Housings
Membrane Housings

RO Membrane Housings For Standard Size Reverse Osmosis Membranes

More

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

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.

SEE OUR ONLINE HELP GUIDE

Compare Products
  1. Remove This Item
Compare
Clear All
You have no items to compare.
My Cart

  1. ​

Filter Change Email Reminder

My Wish List
Last Added Items
  1. Add to Cart
    Remove This Item
Go to Wish List
You have no items in your wish list.