How to Oxygenate a Pond
An air pump is a no-nonsense form of aeration that simply injects a stream of air into the water. This air-stream is diffused where it enters the pond water (near the floor if possible) by an air-stone. The air-stone forces the air into multitudes of tiny bubbles so it is more readily dissolved into the water. Simple air pumps are inexpensive but the unit itself must be kept dry (typically the unit would be housed in a garage or out-building with the air-hose running outdoors). All-weather air pumps are more powerful, offer quiet operation and can be left outdoors. Another very popular approach is that offered by solar air pumps – these are lower power but need no wiring-up, can be left outdoors and work when the sun is out – just when the pond needs more oxygen. You can find our air pump range here.
Diffusers
There are many types of diffusers on the market and they are the most effaced form of mechanical aeration. Air bubbles are passed through the water releasing oxygen as they go. Look for diffusers that produce large numbers of fine bubbles which will be far more efficient. Large bubbles may look better, but a stream of few large bubbles will have a smaller contact areas with the water. Air-stones can also be used with a diffuser, or pump and venturi.
Oxygenator Plants (Useful Blogs: Pond Plants)
Oxygenators are submerged plants are positioned on the pond bed. Most remain completely submerged although a few do produce flowers that peep through the water surface. These are fast growers and breathe vast levels of oxygen into the water during the day.
However the irony is that while they produce oxygen in the day they consume it at night, exuding carbon dioxide. The oxygen levels of a pond may drop overnight if the oxygenator plants are allowed too much space; they can overwhelm and smother a pond.
Add Shade (Useful Blogs: Why Temperature plays a big role in Pond Development)
Providing shade onto the pond helps to reduce the temperature of the pond, which can reduce the amount of oxygen your fish require! This is because the metabolism of your fish will increase in higher temperatures, thus increasing the amount of oxygen they need. A neat way to add shade is by canopies or by adding floating planters. One of our most popular floating planters sets is the Moerings Floating Pond Planter with Three Pond Plants, as it includes everything you need to get the floating planters started.
Fountains and Falls
Oxygen enters the pond anywhere the water is in contact with the air. Increasing the surface area naturally raises the amount of oxygen in the pond and that – by disturbing the water surface and creating ripples is exactly what fountains and waterfalls do. As such, they serve both a decorative and functional role in a pond disturbing the water to keep oxygen circulating and prevent stagnation and the growth of the dreaded blanketweed. You can find our full range of waterfalls using this link and our range of fountain pumps here.
When building a waterfall or stream the flow rate of the pump is vital as this will dictate the effect of the feature being created.
- For each 10cm width of waterfall or stream you will need 1000 litres per hour at the starting or top point of the feature.
- For every metre above the surface of your pond, you will need 1000 litres per hour.
Therefore if the waterfall or stream is 50cm wide and 1m above the pond surface, it needs to have a pump that can push at least 6000 lph flowing over the start to ensure the feature looks good and has the desired effect.
Most pumps follow the same flow rate loss per height curve, i.e. at 0m head height the flow is generally the size of the pump, at 1m head height the flow is slightly less, at 2m the flow is reduced by more up to the max heads height which is where the flow rate is 0 lph and therefore the water will just not flow.
One last point to mention is if the waterfall is being built from scratch and is not part of a pond then a header pool and a bottom reservoir may need to be built to ensure there is sufficient water to run the feature. A stream may require the same construction if it is not part of pond.