GrowoniX GX400 400 GPD Reverse Osmosis Filter
- Produces 400 gallons per day at a 2:1 waste ratio
- Includes a manual flush valve to clear mineral buildup
- Compatible with booster pump to increase system pressure to 80 psi
- View More Details
Earn 586 points for shopping and get $5.86 off your next order. Join Harvest Club for free.
Commercial & Bulk Purchasing
We support operations & licensed facilities with volume pricing, dedicated account managers, and custom equipment consultation.
Who This Is For
- You are scaling up your water production because your current system cannot handle the increased volume of your expanding canopy
- You are looking to reduce long-term operating costs because your current 4:1 waste ratio is driving up your monthly utility bills
What We Found
- The manual flush valve is worth using weekly because it stops mineral buildup before it hardens on your membranes
- We recommend the KDF85 upgrade if your incoming water has iron or sulfur because it protects the membranes much longer
What Users Say
- Operators who switched to the 2:1 waste ratio say their water bills dropped enough to pay for the unit in under a year
- Users who added the booster pump say they stopped waiting on their reservoirs to fill during peak demand times
GrowoniX GX400 400 GPD Reverse Osmosis Filter
Scaling up water production shouldn't mean sacrificing efficiency or quality. The GrowoniX GX400 delivers 400 gallons per day — 17 gallons per hour — of purified RO water at an industry-leading 2:1 waste ratio, pairing high flow output with water savings that competing systems in this class simply can't match. Dual High Flow Cold Water membrane elements power the output, while dual o-ring fittings and GrowoniX's patented GX Series bracketing system ensure a leak-free, durable build designed for the long haul.
Every GX400 is designed, hand-built, and tested in the United States using American-made fittings, tubing, and steel powder-coated brackets fabricated in Los Angeles, California. A 2.5" stainless steel liquid-filled pressure gauge gives real-time system monitoring, and a manual flush valve lets you actively purge TDS and mineral buildup from the membranes to extend their service life. The included Eco Green Coconut Carbon filter covers chlorine reduction for up to 16,000 gallons, and the high-flow pleated sediment filter is fully washable and reusable to minimize ongoing consumable costs.
For growers who need even more output, the GX400 is compatible with an optional booster pump that raises system pressure to 80 psi, increasing daily gallon production beyond rated output. For city water with chloramines or well water with iron and hydrogen sulfide, the optional KDF85/CAT carbon filter upgrade handles both — lasting twice as long as the standard green carbon filter and adding bacteriostatic protection against microbial growth inside the housing.
Product Overview
Features
400 GPD Dual-Membrane Output
Two High Flow Cold Water membrane elements combine to deliver 400 gallons per day — 17 gallons per hour — of purified RO water at a consistent 96% salt rejection rate.
2:1 Industry-Leading Waste Ratio
Two gallons of purified water produced for every one gallon sent to drain — cutting water waste in half versus standard 4:1 systems and lowering long-term operating costs.
Hand-Built in the USA
Each GX400 is designed, assembled, and tested in the United States using American-made fittings and tubing, with powder-coated steel brackets fabricated in Los Angeles, CA.
Manual Membrane Flush Valve
Built-in flush valve routes full feed-water pressure through the membranes to purge accumulated TDS and mineral deposits, significantly extending membrane service life.
2.5" Stainless Steel Pressure Gauge
Liquid-filled stainless steel gauge provides accurate real-time pressure monitoring — protecting membranes and giving you a clear view of system performance at a glance.
Booster Pump Compatible
Pair the GX400 with an optional booster pump to raise system pressure to 80 psi and push daily output beyond the rated 400 GPD for high-demand grow operations.
What's Included
- 2x High Flow Cold Water Membrane Elements
- 1x Electrogalvanized Powder Coated Steel Bracket Set
- 1x Membrane Flush Kit
- 1x 2.5" Stainless Steel Liquid-Filled Pressure Gauge
- 1x Eco Green Coconut Carbon Filter (16,000-Gallon Chlorine Rating)
- 1x High Flow Pleated Sediment Filter (Washable & Reusable)
- 1x Auto Shutoff Valve
Specifications
| Specification | Value |
|---|---|
| System Ratio | 2:1 |
| Nominal Salt Rejection | 96% |
| Permeate Flow | 400 GPD / 17 GPH |
| Min Feed Flow | 0.83 GPM |
| Max Feed Water TDS | <2,000 ppm |
| Feed Temp Range | 40°F – 90°F (4.4°C – 32.2°C) |
| Ambient Temp Range | 40°F – 115°F (4.4°C – 46.1°C) |
| Feed Pressure Range | 45 – 80 psi |
| Max SDI Rating | <3 |
| Max Feed Hardness | 0 gpg |
| pH Range (Continuous) | 5 – 11 |
| Max Turbidity | 1 NTU |
| Feed Connection | 3/8" Tube |
| Permeate Connection | 1/4" Tube |
| Concentrate Connection | 1/4" Tube |
| Dimensions (L × W × H) | 14" × 7" × 21" |
How-To Videos
Connecting Your GX400
Flushing Filters & Initial Start-Up
FAQs
The GX400 uses dual High Flow Cold Water membrane elements tuned specifically for maximum efficiency, producing 2 gallons of purified permeate for every 1 gallon sent to drain. This is a significant improvement over the standard 3:1 or 4:1 ratios found on comparable systems, reducing water waste and lowering utility costs over time.
Yes — the GX400 is compatible with an optional booster pump that raises system feed pressure to 80 psi, pushing daily output beyond the rated 400 GPD. This is ideal for high-demand grow operations where water production is a bottleneck.
The included Eco Green Coconut Carbon filter is rated for chlorine reduction only — chloramine removal requires the optional KDF85/CAT carbon filter upgrade. The KDF85/CAT filter also addresses iron, hydrogen sulfide, and heavy metals for well water applications, and lasts twice as long as the standard green carbon filter.
The GX400 includes a manual flush valve that directs full feed-water pressure through the membranes to dislodge and expel accumulated TDS, minerals, and contaminants. Flushing is recommended at initial start-up and periodically during routine maintenance — watch the Flushing Filters & Initial Start-Up video above for a complete walkthrough.
The GX400 requires a minimum feed pressure of 45 psi and a maximum of 80 psi. Most standard municipal and commercial water lines fall within the 50–70 psi range, making the system plug-and-play compatible for the majority of facilities without additional pressure equipment.
The GX400's high-flow pleated sediment filter is fully washable and reusable — simply rinse it clean under running water during routine maintenance. This reduces ongoing consumable costs compared to systems that require disposable sediment cartridges on a fixed replacement schedule.
Every GX400 is designed, hand-assembled, and tested in the United States using American-made fittings and tubing. The powder-coated steel brackets are fabricated in Los Angeles, California, and all components are housed within GrowoniX's patented GX Series bracketing system for a durable, professional-grade build.
Questions About This Product?
Our specialists are happy to help. Call us or send a message and we'll get back to you within one business day (most of the time within a few hours.)
Why Trimleaf
Equipping home growers, craft producers, and commercial operations across North America since 2016.