Submersible Water Pumps




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.

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

Grech Function Curves

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.

Grech Explosive Picture