POND AERATION IS CRITICAL FOR A POND’S SUCCESS
The most important factor in ensuring the success of a large pond or lake is proper pond aeration. Dissolved oxygen is a critical component in the exology of a pond. It is what makes the pond go and what keeps the inhabitants healthy and keeps the water clean.
To be technical, dissolved oxygen is gaseous oxygen dissolved in an aqueous solution. So basically it is the amount of oxygen available in the pond water. Generally speaking 5ppm is the baseline for what is good for a pond or lake. Anything below that can lead to problems.
Benefits of Aeration
Fish kills (due to low oxygen) can be prevented
Beneficial pond bacteria is stimulated to efficiently break down waste and reduce the bottom muck layer.
Pond water is destratified leading to the prevention of turnover and improved overall water quality.
The need for maintenance products are reduced to the ponds natural ability to regulate itself.
Gasses such as carbon dioxide and hydrogen sulfide can be vented
So what are the problems associated with low dissolved oxygen and what causes them? The most critical problem associated with low oxygen levels is a fish kill. Fish require a certain ppm of dissolved oxygen to live and without it…well they die. Poor oxygen levels can also lead to noxious odors coming from the pond as the break down of organic waste will shift from an aerobic process to a slower anaerobic process that results in the production of hydrogen sulfide. Also, in the case of deeper ponds, the lack of oxygen will lead to stratification, meaning there becomes a layer at the bottom of the pond that becomes unusable as it is extremely oxygen deficient. This in turn reduces the available living space of the fish, placing more strain on the still oxygenated water.
The issues that cause the oxygen levels to become low are numerous. Probably the most common is an over abundance of aquatic plants, particularly algae. Aquatic plants are good in moderation as they do release oxygen into the water. In the case of algae, planktonic algae make up the base of the food chain in a pond and are therefore critical. However many of these plants that release oxygen during the day, also consume oxygen at night. So when you have a pond with a heavy algae bloom or thick aquatic vegetation, oxygen can be rapidly consumed overnight and even on cloudy days, causing a fish kill.
Other factors that contribute to poor dissolved oxygen levels and the need for pond aeration is a high organic waste load. Organic waste in a pond can come from a variety of sources including dead vegetation, fertilizer run-off, fish food and fish waste. All of those examples are naturally broken down in a pond, but to do so efficiently and without further detriment to the water quality, oxygen is needed. So when you have a high waste load to be degraded, you will require a large amount of oxygen to do so.