Aeration Systems for Lakes and Ponds

Ponds and lakes are a valuable natural resource. They add to the beauty of the landscape, provide recreation, and are a habitat for fish and wildlife. However, the good health of a pond is held in a delicate balance. Aeration is THE most important factor in creating a healthy pond or lake. Aeration is what makes the water clean and its inhabitants healthy. Dissolved oxygen is a critical component in the ecology of a pond.

To aerate a pond basically means to dissolve oxygen into the water. Aerating a pond means to make the water more oxygenated. A healthy baseline oxygen level for a pond or lake is approximately 5 ppm. Anything below that will lead to problems.

The most critical problem with low oxygen levels in a pond or lake is a fish kill. If fish do not have a proper level of dissolved oxygen in the water 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 un-usable 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

What is the cause of low oxygen levels? The most common cause is the over abundance of aquatic plants, specifically algae. Aquatic plants are great in moderation. They do release oxygen into the water. Planktonic algae make up the base of the food chain in a pond. The problem begins because many of these plants that release oxygen in the day also consume oxygen at night.  So when you have a pond with a heavy algal bloom or thick aquatic vegetation, oxygen can be rapidly consumed overnight and even on cloudy days, causing a fish kill.

Another factor that contributes to poor dissolved oxygen levels and the need for pond aeration is a high organic waste load.  Organic waste comes from a variety of sources that include fish waste, fish food, dead vegetation and fertilizer run-off. The more waste you create, the more oxygen you will need to break it down in an efficient manner.

There are two main types of aerators, surface aeration and bottom aeration. Surface aerators are useful on ponds or lakes that are less than 6 feet deep. Deeper ponds and lakes will benefit more from a bottom aeration system.

Surface aerators are generally floating aeration units that pull in water from the top foot or so of the pond and splash it into the air. A few types of surface aerators are waterfalls, fountains, spitters, and bubblers. These all are aesthetically pleasing as well as a functional accessory to your pond or lake.

Bottom based aeration systems involve pushing air down to the bottom of a pond or lake and allowing the bubbles to naturally rise to the surface.  These aeration units are the most efficient for aerating deeper pond and lakes as the bubbles are providing the bulk of the work. A pond’s condition deteriorates when the bottom environment cannot support animal life. The bottom is the area that runs out of oxygen first, it is where the most oxygen is used and it is the farthest from the surface where it is replenished. Without oxygen a lake or ponds self purification capability is not only reduced, it is reversed. The small animals, snails, worms, bacteria, etc., which help keep a pond clean cannot live and the pond’s nutrients are then recycled from the sediment. This forms a layer of muck at the bottom which serves as a fertilizer for weed and excessive algae growth. It could also cause large fish kills. In bottom based aeration systems the bubbles rise, they de-stratify the water eliminating the oxygen poor zone at the bottom and mixing it with the oxygen rich water above creating healthier water.

The benefits to expect from a good aeration systems are numerous. The joy that comes along with a healthy pond or lake is priceless.