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Availability: In stock



Premium RO water system with competitive prices

Designed and Made in USA

KoolerMax 5-stage 75GPD Reverse Osmosis Water System for home drinking water

Model: K-5  Koolermax Series

What is K-5 ?

  • This is a 5-stage 75 gallons per day Reverse Osmosis water system that is installed under the sink for drinking water.  It is designed to purify the tap water into clean and good tasting water.

How does it compare to other brands? 

  • Short Answer:  way-better
  • Long Answer: see below

After extensive research, testing, and collaboration with component manufacturers, we have come up with this U.S. Patented designed that is packed with improvement and enhancement.

This new RO system is loaded with upgraded components to improve its function and capability.  It performs better than any typical RO system in its class.

The improvements are:

Bonus pressure gauge is installed in the system:  The pressure gauge is installed on the bracket after stage 3 to monitor the operating pressure.  When the system is making water, it indicates the operating pressure.  When you see a pressure drop of 15 psi, that means the filters are clogging up, need replacement.



5 micron sediment filter with multi-layer, the outer layer is 20 micron and inner layer is 5 micron, which results in more dirt and sediment holding capacity


5 micron coconut shell carbon with better chlorine and chemical removal capacity


Upgraded faucet are now standard:  The stylish dispensing faucet with ceramic disc shut-off are now standard.  It is a lead-free faucet.  This upgrade ensures the longevity of its function and enhancement of aesthetic.

Water supply/feed water adapter:  Now we give you two sizes of water supply adapters,  1/2" MPT and 3/8" compression.  Since newer plumbing under the sink and newer kitchen faucets are using 3/8" compression fitting, we now also include a brass type 3/8" compression adapter.


Clear housing for the first stage sediment filter:  Using the clear housing is an easy way to tell if the first stage sediment filter is getting dirty or clogging up.


New design of auto-shut-off valve:  It looks the same outside but it's new seal design provides more accurate shut-off and higher shut-off pressure. 


Parts bag:

1.  Color tubing, 4 sections of 5 feet tubing 1/4" OD

2.  Drain saddle clamp

3.  Bottom filter housing wrench and Membrane filter housing wrench

4.  1/2" MPT feed water adapter

5.  Inline ball valve, on/off for water supply

6.  Brass type 3/8" compression fee water adapter

7.  Tubing insert

8.  Tank ball valve, on/off ball valve for output

9.  Male elbow fitting, 1/4"MPT, 1/4" tubing, compression type


This is a complete system ready to be installed.  It includes all filters, storage tank (holds 2.5 gallons of water), faucet, tubing, installation hardware, installation manual. 

  • The system come with high capacity filters, you only need to replace the pre-filters and post filter once a year instead of every 6 months, the cost is less than $40 for 4 filters which you replace once a year. You can purchase this filters from us anytime.
  • We offer one year limited warranty for parts and components.
  • We also guarantee the performance of the RO systems
  • Local pickup NOT available
  • Free Tech support
  • We carry all parts and components
  • This is a complete system with all filters, storage tank, faucet, tubing, feed water adapter, drain saddle valve, installation manual.  Ready for installation.

1st stage:  high capacity, 5 micron sediment filter, to remove sediment, rust, sand, (replace every 6 - 12 months)

2nd stage:  high capacity carbon filter, coconut shell carbon block filter removes chlorine, taste, & chlorine (replace every  6 - 12 months)

3rd stage:  high capacity carbon filter, coconut shell carbon block filter further removing chlorine to ensure 100% removal of chlorine (replace every  6 - 12 months)

4th stage:  TFC-75 Premium membrane we use genuine US MEMBRANE membrane filter, 75-85 gal/day, it removes 95% to 98% of all chemical, dissolved solids in tap water. (replace every 2-3 years)

5th stage:  high capacity final stage inline carbon filter, granular activated carbon, to improve taste of water. (replace every 12 months)


Dimension:  RO unit, 16" width, 17" height, 5.5" depth;  pressure tank, about 10" diameter 15" height (holds about 2.5gallons of water)

** Important Note:

All reverse osmosis systems, residential or commercial, are required to have drain water when making pure water.  Our RO systems have built-in auto-shut-off valve so when the storage tank is full, the system shuts off automatically.  The ratio of pure water to drain water for our RO systems are 1:3 (calculated).  Average RO systems are typically 1:4, so our RO systems run more efficiently.  Minimum water pressure required to operate the system is 45 PSI. Ideal pressure is 85 PSI.

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