How to Choose Air Pumps (Air Compressors) for Ponds: Aeration of Large Ponds is Important! An air pump also referred to as an air compressor, and, in a pond, serves two purposes:
- To ensure the oxygen concentration in the water is maintained at a stable level to ensure effective biofilter operation (bacteria in the filter consume oxygen) and
- To provide a degree of vertical mixing of water
An air pump is especially important in hot and humid environments… just like Durban in Summer. The ideal place to add air to a pond is actually at the inlet to the biofilter or even inside the biofilter. This ensures the bacteria required to purify the pond water are at their most active.
It’s almost impossible to add too much oxygen to a pond so go for the largest air pump you can afford.
How to choose the right air pump for your pond
The output of an air pump (air compressor) is determined by the back pressure on the pump (in a pond this is the head of water above the air pump) and the model of the pump. The graph below shows the expected air flow against different pressures.
For example a pond with a depth of 2 metres creates a back pressure on an air pump of approx 0.02 Mpa… therefore the deeper the pond the less will be the flow of air from the pump.
Special rubbers help to keep a steady air output and pressure, an advanced air compressing system; damping system & multi-level muffler make these air pumps extremely quiet. The compact structure of these air pumps is made of an aluminium alloy which gives quick heat dissipation & a long service life. The V-series super silent is truly it’s name-sake with a double damping system. The low power consumption makes it an energy saver and with it’s high quality aluminium alloy casing it has a long service life as well as being compact & light weight.
In the graph below 0.01 Mpa = 1 metre depth approx.
Never install an air pump below water level because siphoning will take place if the air pump stops.
We can also supply more powerful air pumps (more like small compressors) for special needs… give us a call
Air Pump sizing
In order to have a healthy pond environment you need a biological filter, good aeration, a circulation pump and adequate space. It is important to note that all of these elements must work in harmony with one another.
The filtration system purifies the water of wastes, bad bacteria and other toxins; an aerator supplies air to the water so the fish will have oxygen and the water does not stagnate; the pump moves the water through the filter and aerator. This cycle is the lifeblood of a pond. Koi need oxygen and the beneficial bacteria that keep the water healthy also need oxygen (this is why pumping air into water which feeds to a biofilter is beneficial (in fact the best place to add air into the pond system is directly into the bio-filter system as close as possible to where the bacteria are “sitting”. )
Try to add as much air to your pond as you can using air pumps and air stones to distribute the air (especially recommended for ponds that are heavily stocked). You can add the air directly to the pond, the filter, the waterfall or anywhere else you can think of. The amount of oxygen water can hold is dependent upon atmospheric pressure; salinity and temperature. Water can hold less oxygen at higher altitudes. The most important factor is water temperature, as it increases the amount of oxygen water can hold decreases. This is why oxygen levels decrease in the summer season:
Water can hold less oxygen as it becomes warmer. Respiration rates of both plants and animals increase with the warmer water, so more oxygen is used. Summer’s still, hazy or cloudy days may reduce the amount of oxygen produced.
Large amounts of feed given to fish at this time of year result in large quantities of fish waste which create a higher demand for oxygen.