A pond pump does more than move water. In a fish pond it keeps the water circulating and oxygenated so it stays clear and healthy. In a water feature it creates the flow over a waterfall or through a fountain. Choosing the right one comes down to three things: the size of your pond, how fast the water needs to circulate, and what the pump has to handle.
The full range is on our pond pumps collection.
Step 1: Work out your pond volume
Everything starts with volume. For a roughly rectangular pond, multiply length by width by average depth in metres, then multiply by 1,000 to get litres. A pond 3m long, 2m wide and 0.5m deep holds about 3,000 litres. For irregular shapes, a sensible estimate is fine.
Step 2: Decide how fast the water must circulate
This figure sizes the pump, and it depends on what the pond contains. The more fish, the more waste, and the faster the water must be turned over:
- Natural or planted pond: circulate the whole volume about once every two hours.
- Goldfish pond: waste builds faster, so circulate once every one and a half hours.
- Koi pond: heavily stocked, so circulate once an hour, with strong filtration to match.
If the water is not circulated enough it can stagnate, toxin levels rise, and the fish can suffer from lack of oxygen. Turn your volume into a flow rate: a 3,000 litre goldfish pond circulating every one and a half hours needs to move about 2,000 litres an hour. That is your starting point, but head reduces it, which is the next step.
Step 3: Allow for head, especially with a waterfall
The flow figure on a pump is its maximum with no lift. Asking it to push water up to a waterfall, through a filter or out of a fountain reduces the flow, and the higher the lift and the longer the pipe, the bigger the reduction.
So if a waterfall sits a metre above the pond, do not choose a pump whose maximum flow only just meets your target, because at that height it will deliver noticeably less. Check the pump's flow at the height you actually need. Pipe bore matters too: too narrow a hose throttles the flow before it reaches the feature. A practical tip: avoid clear hose, since sunlight through it encourages algae to grow inside. Opaque hose keeps the water cleaner.
An APP TPS pond pump powering a waterfall installation. Pond pumps such as these are commonly used to circulate water to waterfalls, streams, fountains, and filtration systems.
Step 4: Match the pump to what is in the water
Pond water carries leaves, algae and fish waste, so a pond pump is built differently from a standard pump. Pond pumps use non-clog impellers (the spinning parts inside, shaped to resist jamming on debris) and a sealed, non-toxic oil, so they can run continuously without blocking and without risk to fish. A standard submersible pump used in a pond will often clog, overheat and fail, and if a seal fails it can release oil into the water, so it is worth choosing a pump made for the job.
From our range:
- The APP TP series is our most popular pond pump, built for 24-hour running.
- The APP MH range accepts fountain heads, ideal for water features and waterfalls.
- The high-flow APP HD-15 moves up to 830 litres a minute, suiting large ponds and big displays.
- For circulation on larger ponds, a surface pump such as the Speroni SWIMM, sited dry beside the pond, can be the better choice. On a large pond it is common to run two pumps: one for filtration, one for the feature.
Common mistakes to avoid
- Buying on the maximum flow figure: always check flow at the height you need, not the headline figure.
- Undersizing for fish: a pump suited to an ornamental pond will struggle to keep a stocked fish pond clear. Size on circulation.
- Oversizing a fountain: too powerful a pump overwhelms a gentle fountain and can stress plants and fish.
- Ignoring the filter: if the filter cannot handle the pump's flow, it will not clean properly. Match the two.
- Letting it run dry: keep a submersible pump covered with water, as running dry damages it quickly.
Frequently asked questions
How do I size a pond pump?
Work out your pond volume in litres, then choose a pump that can circulate the whole volume about once every two hours for a natural pond, every one and a half hours for goldfish, or every hour for koi. Then check that flow figure at the actual height the water has to be lifted, not the pump's maximum.
What flow rate do I need for my pond pump?
It depends on circulation. A 3,000 litre goldfish pond circulating every one and a half hours needs roughly 2,000 litres an hour at the real operating height. Koi ponds need faster circulation, around once an hour.
Should a pond pump run all the time?
For a fish pond, yes. Continuous running keeps the water oxygenated and filtered. For a purely ornamental feature you can run it when you want the effect, though continuous running helps prevent stagnation.
Can I use a pond pump for a fountain or waterfall?
Yes, but choose it on flow at the height of the feature, not the maximum. The APP MH range accepts fountain heads and is made for this.
Can I use a normal submersible pump in a pond?
It is not recommended. Pond pumps use non-clog impellers and a non-toxic sealed oil so they can run continuously and safely around fish. A standard pump can clog, overheat and, if a seal fails, release oil into the water.
