Description
Bring your GrowMax 3000 back to full flow and rejection
The GrowMax 3000 500 GPD RO Membrane is the genuine high-flow replacement membrane for the GrowMax 3000 Reverse Osmosis System, GrowMax's largest RO unit. The 3000 runs two of these membranes in parallel to produce up to 125 litres an hour and 3,000 litres a day of purified water, and the membrane is the stage that does the real work, removing up to 95% of dissolved salts and heavy metals so every feed you mix starts from a clean, low-EC base rather than whatever came out of the mains.
Key Benefits
- Genuine GrowMax part – maker reference GMWMAXMEMB, made for the GrowMax 3000 housing
- 500 GPD high-flow rating – two side by side give the 3000 its 3,000 litres a day
- Up to 95% rejection of salts and heavy metals for a low, predictable starting EC
- Restores output when a worn membrane has slowed production
- Brings EC back down when an ageing membrane starts letting dissolved solids through
Why Does My RO Water Keep Creeping Up in EC?
An RO membrane is a consumable. As it loads up, production slows and more dissolved solids slip past it, so the water you treat as pure quietly picks up EC again. On hard UK mains that returning calcium and magnesium eats into your nutrient headroom, skews feed ratios and shows up as pH drift, lockout and poor nutrient uptake that no amount of feed adjustment fixes. GrowMax's own rule is simple: change the membrane when the output EC rises or the water production drops.
How to Use
- Turn off the supply and release the pressure before opening the membrane housing.
- Remove the old membrane and fit the new one the same way round, then close the housing.
- Let the unit run to waste for 15 minutes after fitting a new membrane, as GrowMax instruct, before collecting water for use.
- Change the membranes every 6 months to 2 years depending on use and input EC, and the green carbon block every 6 months – chlorine that gets past a spent carbon block shortens membrane life.
- Keep the GrowMax 3000 on a cold supply of 4–6 bar (57–85 PSI), maximum 25°C.
Technical Specifications
- Type: high-flow reverse osmosis membrane
- Rating: 500 GPD (US gallons per day)
- Fits: GrowMax 3000 Reverse Osmosis System (takes two, running in parallel)
- GrowMax 3000 output: up to 125 L/h, 3,000 L/day with both membranes fitted
- Rejection: up to 95% of salts and heavy metals
- Change interval: 6 months to 2 years, depending on use and input EC
- Supply (GrowMax 3000): 4–6 bar (57–85 PSI), cold only, max 25°C
- Maker reference: GMWMAXMEMB
Frequently Asked Questions
Do I need one membrane or two?
The GrowMax 3000 runs two 500 GPD membranes side by side, and this listing is a single membrane – order two to replace both.
Will it fit the Power Grow 500, Mega Grow 1000 or Maxquarium?
No. Those units take GrowMax's smaller 150 GPD membrane. This 500 GPD membrane is made for the GrowMax 3000 housing.
How do I know when the membrane needs changing?
Check the EC of the water coming out of the unit. When it starts to climb, or the unit takes noticeably longer to fill your tank, the membrane is wearing out – typically somewhere between 6 months and 2 years depending on how hard your water is and how much you run it.
Will it take my water to 0 ppm?
RO removes up to 95% of dissolved solids, so on hard water expect a low reading rather than zero. For true 0 ppm, growers add a de-ionisation stage after the RO.
Works Well With
