Spare Maxi-Jet Impellors - Replacement Parts for MJ-500 and MJ-750 Pumps
Best for: Anyone running a Maxi-Jet MJ-500 or MJ-750 submersible pump whose impeller has worn out, jammed, or gone missing.
Our thoughts
Impellers are the one part on these pumps that actually wears - everything else on a Maxi-Jet tends to run for years. Rather than binning a perfectly good pump body over a worn impeller, this gets it back to full flow for a few quid. Just make sure you order the right model number, MJ-500 and MJ-750 impellers aren't interchangeable.
This is a genuine replacement impeller assembly for the Maxi-Jet (Newa) MJ range of submersible pumps, commonly used to circulate nutrient reservoirs, feed aeroponic systems, and drive fountains or powerheads. The impeller is the spinning rotor inside the pump housing that actually moves the water - it's the part most likely to pick up grit or mineral scale over time and lose efficiency.
Sold as a direct fit for the two most common Maxi-Jet models in grow room use: the MJ-500 and the MJ-750. Simply match the model printed on your existing pump housing to the correct impeller size.
How it compares
Impeller kits are a standard part of keeping any submersible pump running, not just Maxi-Jet's.
- Cheaper than replacing a whole MJ-500 or MJ-750 pump when the motor housing and magnet are still fine
- Genuine like-for-like fit avoids the tolerance issues you get trying to force a generic impeller from a different brand, such as Hailea or Sicce pumps, into a Maxi-Jet housing
- Straightforward DIY swap - no specialist tools needed, unlike a full pump strip-down
A cheap way to get another year or two out of a pump you already know works.
Usage guidance
Identify your model
Check the model number moulded into the pump body or on the original packaging - MJ-500 and MJ-750 impellers are sized differently and won't fit each other's housing.
Fitting
Unplug the pump, remove the front cover/cage, and slide out the old impeller assembly. Rinse any scale or debris from the impeller chamber before fitting the new impeller, then refit the cover.
Maintenance tip
Rinsing the impeller chamber every few weeks in hard water areas will slow scale build-up and extend the life of the new impeller.
Technical specifications
- Compatible models: Maxi-Jet MJ-500, Maxi-Jet MJ-750
- MJ-500 rated flow: approx. 490 L/H
- MJ-500 power draw: approx. 6W
- MJ-750 rated flow: approx. 670 L/H
- MJ-750 power draw: approx. 7.5W
- Fitting: Direct replacement, no tools required
- Use: Submersible, suitable for nutrient reservoirs and aeroponic/DWC systems
Who this is for
- DWC and aeroponic growers whose Maxi-Jet pump has slowed down or stopped moving water properly
- Anyone with grit or scale-damaged impellers from hard tap water or mineral nutrients
- Growers who'd rather spend a few pounds on a spare part than replace a working pump
Our take
The impeller is a wear part by design, so having a spare on hand just makes sense if you're relying on a Maxi-Jet to keep your reservoir or aeroponic system running. It's a five-minute fix that saves buying a whole new pump.
One we sell a lot of for growers topping up their spares box - at a price that makes sense.
