Growmax Mega Grow 1000 - 1000 Litres/Day Reverse Osmosis System
Best for: Growers with two or more reservoirs, or one large one, who need genuinely low-EC water and have outgrown a smaller RO unit.
Our thoughts
This is the sensible middle ground in GrowMax's RO range - twice the output of the Power Grow 500 without jumping all the way to the Pro 3000's commercial price tag. If you're regularly running out of pure water before your reservoirs are full, this is the upgrade that actually fixes it rather than just delaying the problem.
The GrowMax Mega Grow 1000 is a reverse osmosis system built to produce up to 1,000 litres of pure water per day. Mains water passes through a sediment pre-filter, a carbon block to strip chlorine and organic contaminants, and then an RO membrane that rejects around 95% of dissolved salts and heavy metals and up to 99.9% of chlorine - leaving you with consistently low-EC water for mixing nutrients from scratch. It runs on mains pressure, with an automatic shut-off valve and flow restrictor built in, and is designed to work best at an inlet pressure of roughly 3-5 kg/cm² (around 43-71 PSI) and a feed water temperature near 25°C.
Because it produces genuinely demineralised water rather than just dechlorinated water, it's also handy beyond the reservoir - the output is well suited to humidifiers and misters, since it won't leave the white mineral residue that hard tap water does, which keeps that equipment running cleaner for longer.
How it compares
It's the mid-tier RO system in GrowMax's own line-up, sitting above the Power Grow 500 and below the Pro 3000 on output.
- Output of 1,000 litres/day is double the Power Grow 500 (500L/day) and roughly a third of the Pro 3000 (approx. 3,000L/day) - a genuine step up for a multi-reservoir setup without paying commercial-unit prices.
- Against HydroLogic's Stealth-RO150 (around 560 litres/day), the Mega Grow 1000 comfortably out-produces it, putting it closer to the territory of HydroLogic's larger Evolution RO1000 system.
- Unlike GrowMax's carbon/sediment-only filters (Eco Grow 240, Garden Grow 480, Pro Grow 2000), this actually reduces dissolved salts rather than just chlorine and grit, which matters if your feeding programme depends on starting from a known, low EC baseline.
If a smaller RO unit is leaving you waiting around for water, this is the upgrade that fixes that without overspending on capacity you don't need.
Usage guidance
Plumbing it in correctly and keeping an eye on pressure gets the best out of it.
Installation
Connect to a mains cold water supply, keep inlet pressure within the recommended 3-5 kg/cm² range, and route the purified line to your storage tank or reservoir with the waste line going to drain.
Water quality
The system is designed for feed water at or below around 550ppm TDS - if your local mains water is unusually hard, output and membrane life may vary from the stated figures.
Pressure limits
Don't run it above roughly 80 PSI inlet pressure, and avoid installing it where water hammer or pressure spikes are a known issue, as this can stress the membrane and shorten its life.
Technical specifications
- Output: up to 1,000 litres/day
- Salt/heavy metal reduction: up to 95%
- Chlorine reduction: up to 99.9%
- Optimal inlet pressure: 3-5 kg/cm² (approx. 43-71 PSI)
- Maximum inlet pressure: 80 PSI
- Optimal feed water temperature: around 25°C
- Recommended feed water quality: 550ppm TDS or below
- Included: membrane housing, purified/waste water lines, automatic shut-off valve, flow restrictor, sediment filter, carbon filter, RO membrane, pressure gauge, outlet tubing
Who this is for
- Growers running two or more reservoirs who keep running short of pure water
- Anyone whose feeding programme depends on starting from consistently low EC water
- Growers wanting cleaner water for humidifiers or misters without mineral scale build-up
- Setups too big for the Power Grow 500 but not big enough to justify the Pro 3000
Our take
The Mega Grow 1000 hits a genuinely useful middle ground - real RO performance, real output, without the commercial price tag of GrowMax's biggest unit. For most multi-reservoir home and small commercial grows, this is enough capacity without any excess.
Reliable performance without overpaying for features you don't need. One we sell a lot of for growers stepping up from a smaller RO unit.
