One of the most important factors to consider with a lake is the amount of dissolved oxygen (DO) in the water. Just like us, fish need oxygen to survive. So how do you know if you have enough oxygen in the lake? Typically measured in parts per million (PPM) you should be aiming for a minimum DO level of between 4 and 5 PPM.
If the amount of dissolved oxygen is lower than this and you have fish in the lake, you put them at risk of dying from suffocation. Stratification, or an oxygen deficient layer of water at the foot of the pond is another possible side effect of low oxygen levels, this can cause plant life in that layer of the water to die and if this is not removed it will rot causing silt and the build up of nitrate and nitrate levels, eventually leading to a build up in ammonia. In addition you risk releasing dangerous toxins in to the atmosphere from potential anaerobic waste digestion.
So what causes low dissolved oxygen levels? Excessive amounts of Algae and aquatic plants are the main culprits because they absorb a great deal of oxygen after nightfall. An abundance of organic waste i.e high silt levels will also cause a reduction in oxygen levels and silt can also release harmful gasses into the water. Finally, having too many fish can also reduce the oxygen levels not only through lack of oxygen per fish but high waste inputs into the water.
In a natural, balanced and well managed lake there would be little requirement for aeration but due to pressures exerted on many water bodies, especially during the the spring and summer season, supplementary aeration is an essential management tool. Oxygenation is not just important for fish, but for everything else as nearly every biological process that takes place within water is dependent on a readily-available supply of oxygen. This dependency on oxygen occurs across all levels, including the microscopic bacteria that are essential for the processing of organic waste, the oxidisation of silt, the processing of harmful gasses or nutrients or and the numerous other processes that take place in a lake to maintain healthy water.
One way of solving the problem of insufficient oxygen levels in a lake is to install an aeration system. For shallow water bodies, less than six feet say, a surface aerator might be a useful investment. Water is extracted from the top layer of the lake's surface and dispersed into the air. Upon landing it facilitates an oxygen exchange helping to aerate the top few feet of the pond or lake's surface.
If however you have a deeper pond or lake, a bottom based diffuser system that forces air down to the base of the pond, enabling it to bubble back up, may be the better bet. The threat of stratification is also reduced as sufficient oxygen levels at the foot of the pond are maintained. Although a bottom based diffusers might be the most effective it may not be the best choice for the lake. An alternative option that can increase the amount of oxygen in a lake, whilst reducing the silt levels, is to use a product called AlphaSilt. This product was developed by Heathland Aquatic Engineering and is the most effective Silt digesting product on the market, follow the link to read more about AlphaSilt.
Aerators are very beneficial as they not only protect your fish by maintaining healthy oxygen levels, they constantly stimulate good aerobic bacteria and eliminate unwanted nutrients, which are a cause of algae outbreaks or blooms. Noxious smells are also reduced and overall water quality is improved. Silt reduction would also be a benefit of increased oxygen.
While aeration systems are certainly not cheap they are an important investment for a lake that will save you time and money in the long run. Heathland Aquatic Engineering has a vast range of aerators to hand which with the help of our experienced team of engineers enables us to choose the aerator that best suits your needs.
We supply all aeration and fountain equipment and our installation services to domestic and commercial clients in Norfolk, Suffolk, Essex, London and Kent and throughout the United Kingdom. For more information and advice about aerating your lake or pond or lake and pond maintenance and fountains for lakes and ponds please email [email protected], call 0800 3891990.