Submersible Water Pumps
R140.00 – R550.00
Keep nutrient-rich water moving through your system, reliably. Submersible Water Pumps circulate solution in NFT and other hydroponic setups — pick the right one for how high it must lift the water, and enjoy dependable flow.
- Right pump, right system: choose by head height (where the pump stops lifting); NFT needs 1–2 L/min per channel
- Fine-tune your flow: go slightly larger than your minimum and throttle back with an inline tap
- Doubles as an aerator: a 2nd venturi fitting aerates tanks (works best on the HJ-942 and up)
- Easy upkeep: includes a filter sponge — rinse it clean regularly with a little soap
Grech range, 230V AC mains. HJ-542 400L/h/0.8m/12mm/5W; HJ-742 600/1m/12mm/8W; HJ-942 800/1.3m/12mm/16W; HJ-1142 1000/1.6m/15mm/22W; HJ-1542 1400/2m/20mm/28W; HJ-1842 1800/2.5m/20mm/40W. Larger models need a hose clamp; each comes with 2 pipe fittings.
Description
Submersible Water Pumps are used to circulate nutrient-rich water in NFT and other hydroponic systems.
Choosing the right water pump will be determined by how high the pump would need to lift the water. ( In the table below the listed Head Height is the height where the pump basically stops pumping any water. ) The prescribed flow rate for NFT hydroponics per channel is between 1 and 2 liters of water per minute. Choosing a pump slightly larger than the one that meets your minimum requirements is advised, as the flow rate can then be throttled back slightly by using an inline tap.
THESE PUMPS ARE 230V AC (Mains Power)
| Model | Output | Head | Pipe Fitting Size | Power Consumption |
|---|---|---|---|---|
| Grech HJ-542 | 400 L/h | 0.8m | 12mm | 5w |
| Grech HJ-742 | 600 L/h | 1m | 12mm | 8w |
| Grech HJ-942 | 800 L/h | 1.3m | 12mm | 16w |
| Grech HJ-1142 | 1000L/h | 1.6m | 15mm | 22w |
| Grech HJ-1542 | 1400L/h | 2.0m | 20mm (Needs hose clamp) | 28w |
| Grech HJ-1842 | 1800 L/h | 2.5m | 20mm (Needs hose clamp) | 40w |

The Grech pumps come with 2 pipe fittings, the standard fitting (mentioned in the table above), used to connect to piping to lift/move water. The 2nd fitting ( with the little T-piece on the side, attached to clear piping ) is actually a venturi adaptor and can be used to aerate tanks of water, INSTEAD of lifting/moving water. This venturi really only works well on the larger models (HJ-942 and up) and is also dependent on how deep the pump is submerged. THIS video shows how a venturi can be used to aerate and agitate water.
The Grech pumps come with a filter sponge and needs to be cleaned regularly. All you need to do is put a dab of soap on it (optional) and work it in under running water, then rinse it out thoroughly.













