If you’re considering building a pond in your garden or a dam on your farm, or if your existing lake or pond is looking decidedly unhealthy, then you need to read on. It’s about the importance of keeping your water body aerated and it gives a brief overview of some of the ways of doing so.
All ponds and lakes need oxygen to survive and thrive and the natural ecological processes like wind, rain, waves and plant activity generally won’t provide sufficient oxygen to maintain optimum water quality. Installing an aeration system is often the best – and the only – way to ensure sufficient concentration of dissolved oxygen in the water.
But it’s important to know that not all aeration systems are the same, and that any decision on an aeration method shouldn’t be taken lightly. Many factors need to be considered including the size and depth of the pond or lake, whether electric or solar power is preferred, the physical needs of the water body, the location, noise levels, aesthetics and your budget to install a suitably sized aeration system.
There are essentially two types of aerator, a bottom-based system (also known as diffused aeration) and a surface system (fountain aeration) – and the depth of your pond or lake is the best way of determining which one will be best for your application. The rule of thumb is that a surface aeration system will be sufficient for ponds up to six feet in depth and anything deeper will probably need bottom-based aeration.
That said, here are some of the more popular types of aeration system used for effective pond or lake management:
Shallow surface aerators
These are generally floating aeration units that create turbulence on the surface of the water. They operate by drawing in water from a depth of up to 1.5 metres from the pond or lake and splashing it into the air, thereby causing oxygen transfer and the venting of gases by promoting water circulation. Fountains also fall into this category.
Compressed air aerators or diffusers
These are used in deeper and larger bodies of water, utilising compressors situated outside to force air down through self-weighted airlines down to a weighted diffuser at the bottom of the pond or lake. The bubbles that are created then rise naturally to the surface, destratifying the water, mixing poor quality water from the bottom with oxygenated water at the top and creating a healthier equilibrium. Bottom-based systems also appeal to those pond-owners who don’t want to see much agitation on the surface of the water – all that’s visible is a non-invasive gentle rolling action. The Oase Aqua Oxy is the classic among the aerators for ponds up to 50m³ or with a high fish stock.
These also operate on the diffuser principle, and as they don’t require a power source, they are a good choice for lake management in remote locations.
These types of aerator are generally not used in recreational ponds, but rather in fish breeding and bait transport applications.
As you can see, decision-making on what aerator type to choose could be quite challenging. Matching the aerator type to your specific application is crucial however, so decisions shouldn’t be made lightly. Expert advice from an established lake management consultancy such as Clearpond should be the starting point. Calls to them are free, simply dial 1800 222 010 or visit their website www.clearpond.com.au for friendly, professional advice on all things to do with ponds, lake management and aquaculture supplies.