How to choose the right pond pump

If you want to maintain the water quality in your pond and keep it clear and healthy, maintaining an effective filtration process is essential. Choosing a pond pump that can keep up with the water’s demands will be the most important decision for the health of your pond water.  So how can you know which pond pump to choose? Some of the most important factors are flow rate, head height and the running cost.

Flow rate

A pump’s flow rate is one of the most important factors in choosing a pond pump. The flow rate is the volume the pump can process during a given time, usually measured in litres per hour (LPH). A golden rule is that a pump should at least be able to process the entire volume of your pond in 2 hours. So if you have a 2000 litre pond, you need a pump with a minimum 1000LPH flow rate.
If you keep fish in your pond, we recommend an even higher flow rate due to the added need for filtration. Furthermore, if you pump water up from the pond for fountains or waterfall features, you will need to consider the pump’s “head height”.

PS. Any tubing coming from the pump adds friction to the water flow - resulting in less flow. To ensure there is enough flow, add 20% to the flow rate required.

Head heights

The head height for the pond pump details how high the pump can push out water. Each pump has different flow rates at different head heights as the flow goes down as the head is higher. The hed height gives you a good idea if the pump is powerful enough to run a waterfall, filter or fountain.

Submersible vs external pumps

Submersible pumps are the easiest to install as you only need to place them into the pond. External pumps need to have plumbing going through the wall of the pond liner which requires extra care with waterproofing with pond sealer or pond silicon.

Power connections

Pond pumps should never be connected to power through extension cords due to obvious reasons. You might need to get an electrician to install a power point close to the pump. Solar powered water pumps are increasing in popularity, as it both saves on installation costs as well as running costs.
Low voltage pumps are also popular as a safer option, especially around children. Most low voltage pumps come with 11m of cable and the opportunity to extend the cables up to 30m.

Running costs

A cheaper pond pump might work out more expensive in the long run if it is less efficient  with regards to power consumption vs output. A short term saving could end up being a long term liability. The PondMAX EV2 power saver and PondMAX EV2 low voltage pond pumps are great value for money with regards to their lower energy costs, and the latter’s compatibility with solar power as well.
Pond pumps with photocells will turn off automatically when it is dark, helping you save money on power consumption. If you do not have a photocell, you can also use a timer for the power point, to determine which hours of the day the pump should be active.

Tube sizing

Another factor that can impact your flow rate is the diameter of the tubing used. The larger tubes can obviously handle larger quantities of water. Check the table below for recommended tube diameter compared to flow rate.

Flow rate LPH

Tubing Diameter

Flow rate LPH

Tubing Diameter

300-1000

13mm

5000-8000

32mm

1000-2000

19mm

8000-15000

40mm

2000-5000

25mm

15000-20000

50mm

 

And finally: If you are in doubt, remember that you can always throttle back a pump that is oversized with an inline valve; but there is nothing you can do with an undersized pump!