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GrowoniX EX400 - 400 GPD Reverse Osmosis Filtration System

Item #: EX400

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GrowoniX EX400 - 400 GPD Reverse Osmosis Filtration System

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The GrowoniX 17 GPH Reverse Osmosis Filtration System is designed to flow 17 gallons per hour of pure RO water, with an astounding 2:1 ratio-High flow rates and water savings never before seen in a package so affordable and durable. Utilizing the most efficient membrane technology in the world, and equipped with a steel pressure gauge. A manual flush valve allows you to clean the membrane, purging out pollutants that could otherwise add buildup to the system. Flushing adds considerable life to the membrane as well.

Perhaps the coolest feature of the EX400 is that when used with a BP-1530 booster pump, to get the input feed water pressure to 80psi, the filter can produce up 450 gallons per day. No little RO on the planet can match this.

    Growonix EX400 Systems Features:
  • High Flow Cold Water membrane
  • 2:1 system ratio - The most efficient in the industry
  • Electrogalvanized powder coated steel brackets
  • Membrane flush kit
  • 2.5" stainless steel liquid filled gauges
  • One Eco Green Coconut Carbon filter rated for 8,000 gallons chlorine/chloramine reduction
  • High Flow pleated sediment filter, completely washable and reusable
  • Auto Shutoff Valve: for positive automatic shutoff when using a float valve
  • No additional pre-filters needed

Optional KDF85 Carbon Filter Upgrade

For chlorine and chloramines reduction for city water. Also for well water for iron, hydrogen sulfide, and heavy metals reduction. Will last TWO TIMES AS LONG as the standard green carbon filter. Prolongs the life of the membranes. Reduces chloramines, chlorine, iron, sulfur and heavy metals. Bacteriostatic qualities do not allow microbes to breed in filter.

Optional Accessories for EX400 Systems:

Click here to view the GrowoniX Replacement Filter Chart.

Click here to view the GrowoniX Product Guide.

The EX Series is efficiency at its best. Growonix went back to the drawing board and asked the question, "How can we do the same thing we did with the GX Series, but do it at a special price point, one which opens the doors to everyone wishing to make purified water. without sacrificing the quality that is synonymous with the GrowoniX product line?" With the EX Series, was able to strip out all the non- essential components, and leave in all the high quality parts found in the GX Series. By doing that Growonix reduced the manufacturing cost and passed that savings along to their customers.


Brand GrowoniX
Weight (lb.) 20
Height (in.) 21
Width (in.) 7
Length (in.) 14
Warranty Yes
Free Shipping Yes
Gallons Per Hour 17
GPD 400
Min. NACL Rejection 96%
Min. Feed Pressure 20 PSI
Recommended Feed Pressure 60 - 80 PSI
System Ratio 2:1
Operating Temperature 40°F - 105°F
Operating pH 3 - 11
Nominal % Rejection 98.5%
Max Hardness 15 gpg

GrowoniX EX400 - 400 GPD Reverse Osmosis Filtration System Questions & Answers


How does water temperature effect flow rates through RO filters?
Between 77° and 50° water system production declines by 50%, as cold water is more dense, more viscous, and more difficult to move through the membranes.

What can be done to combat the effects of cold water on RO membranes?
Increasing the water pressure with a booster pump. Increasing the feed water temperature, which some people do by mixing warm and cold water from a diverter valve.


Does the system ratio (waste ratio) change over time?
System ratios can change over time if the flow restrictor starts clogging due to hard feed water conditions.

Does the system ratio change with water temperature?
System ratios (waste ratios) can drift with cold feed water. 
 Water travels the path of least resistance — the drain line! It’s important to check the system ratio during the winter months and adjust if necessary.

How can the system ratio be adjusted?
System ratios can be tuned with a ball valve or Flow Box. Never go lower than the system was intended for.


How much water pressure is needed to run an RO system properly?
RO membranes require 40 psi of incoming pressure to produce even a drop of water except our GXM200-HF which requires only 20PSI.
 The only membrane on the planet that can do this.

What’s the maximum feed water pressure that an RO system should run on?
Incoming feed water pressure on all water filters, always and everywhere, should be no more than 80psi. Plastic filter housings cannot handle more pressure.


Can all GrowoniX water filters be used with well water?
Well water is generally too dirty for small RO membranes (100GPD through 400GPD systems).
 The large 4” membranes of the bigger systems (600GPD and larger) are recommended for well water treatment,
 unless the water demand is really low.

Are there any special filters needed to treat well water?
KDF85/ catalytic carbon filters are a must 
for well water treatment. This premium catalytic carbon filter with a bed of KDF85 media can reduce iron, hydrogen sulfide, heavy metals, and bacteria—all things that wreak havoc on RO components—especially membranes. Other consideration for special filters can only be deduced with a laboratory water analysis.

Does GrowoniX help with well water analysis?
They do. Just send Growonix your water analysis and they will look at it for free. If you don’t have a recent analysis, you can either use a local water lab, or purchase a test kit through GrowoniX send it off to our partner lab.

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