A constantly neglected and underestimated part of a good pond set up is a useful and reliable pond air pump.

Relatively cheap in comparison to the other systems within your pond, they can often make a huge difference to the overall health and wellbeing of your pond, and to the lives of the fish and other organisms that live within it.

What do pond air pumps do?

It’s simple really: Air pumps force fresh air down to the bottom of your pond which is then released through air stones or airline, rising to the surface as bubbles, aerating and oxygenating your pond in the process.

Having a good oxygen level in your pond is important. Without having a good oxygen ratio in your pond water, your fish have nothing to breathe through their gills and quickly suffocate – if you have suddenly gone outside to find that your fish have died overnight, then it is more than likely that a lack of oxygen is the cause, especially as your aquatic plants will have swapped from producing oxygen to using it up as part of their day-night cycle.

Beneficial filter bacteria use up oxygen too, actually competing with fish. So the more oxygen and pond aerators in the water, the more available it is for fish and filter bacteria. You'll have healthier water.

All in all, increasing your oxygen levels increases the ability of your fish to thrive, as well as the other aquatic life and your plants. Increasing oxygen levels is especially important in the summer months too - In hot weather, algae grows faster, using up more oxygen in your pond at night – oxygen that is vital to the wellbeing of your fish.

How do pond air pumps work?

Your air pond pump will generally sit just near your pond. There are models that a pretty weather-proof, but generally they will need to be housed in a dry place nearby, preferably in a large plastic box, or if you want to get creative, some aquarists have managed to make some pretty beautiful home-made-hides for them.

They pump the air down through your airline to the deepest part of your pond, and which point the air is pushed through a porous stone or wooden air-stone, creating a stream of bubbles that allow the oxygenation of your pond. If you want to have multiple air-stones throughout your pond using one singular airpump, you can get manifolds that split the airflow.

Choosing the right pond air pump

As with most things in life, you tend to get what you pay for, and so the chances are that the bigger the price tag, the more reliable your pump will be. That being said, there are some good new brands appearing in the market place that may save you money.

Most air pumps operate extremely well when pumping to a depth of about 3 foot. Any more than that, and some of the light to mid-range pumps might begin to struggle, providing only the off bubble every now and again. The only thing to really make sure of here is that you are buying an air pump that will give you a good flow rate at your chosen depth.

BEWARE: Just because a pump’s description says that it will pump down to a certain depth, does not mean that it will give you the desired flow rate at that depth. Flow rate is in direct correlation with Pond Depth, and the closer you get to operating at the maximum depth, the less the flow rate will become until it is just the odd bubble. Max Depth descriptions mean exactly that – the maximum depth that even the smallest amount of air can be pumped down to.

Take a look at the example graph below (of a hypothetical air pump) to illustrate this: it is a curved line graph, indicating that as depth increases, flow rate begins to taper-off.

So, now you know what they can do, you might want to consider adding an Air Pump to your pond systems.