What’s the first requirement for life? Air, or oxygen. We know that people need oxygen to live. We also know that plants need oxygen for healthy growth. But did you know that ponds need oxygen almost as much? That’s because oxygen is vital not only to fish, but also to the ecological processes that protect water quality and keep it clear.

Plants, wind, rain, waves – all of these add oxygen to the water. But sometimes these are not enough to stop a pond from deteriorating. Installing an aeration system is often the best way to give a pond the oxygen it needs to maintain water quality and reduce algae. Aerators work either by pumping compressed air into and through the water, or by agitating the water surface. As water moves across the surface, it grabs oxygen from the air and releases harmful gases at the same time.

Using an aeration system can help maintain a pond in a number of ways. First of all, if a pond contains fish, aeration is essential. Aerated ponds can support greater concentrations of fish and can literally give them more “room to breathe” by circulating water to eliminate thermal stratification. In a stratified pond, the upper, warmer layer can become oxygen saturated while the lower, bottom layer lacks oxygen. This can greatly stress fish and cause fish kill. Stirring up the layers through aeration can distribute a healthy amount of oxygen throughout the pond. <>
Photo courtesies: Aqua Control (top left, bottom right), Aqua Master (top right, middle), Otterbine Barebo (bottom left)
“Think of it as something similar to swishing your hand around in the bathtub,” says Reanna Pelszynski, general manager of Aqua Control in Peru, Illinois. “As the water moves around, it helps even out the temperature and the oxygen concentration.”

Aeration also provides the oxygen necessary for aerobic digestion of algae, ammonia, and nitrites. Bacteria aid in the decomposition of fish waste, debris, and other organic matter; adding oxygen encourages this process. This protects fish health and helps prevent dead organisms from accumulating as sludge in the lake or pond bottom. It also helps eliminate pond odors.

Photo courtesies: Aqua Master

In addition to improving the chemical balance of the pond, circulating water can also push certain kinds of algae to the sides of the pond where they can be more easily removed. It can help control mosquito larvae as well, because mosquitoes do not breed as freely in moving water.

In some climates, aeration provides enough movement to keep the pond from freezing in winter months and prevents winter fish kill by keeping the water oxygenated. Winter is a critical time for pond health because a pond that is frozen over is deprived of the oxygen it would normally get. Keeping a hole in the surface ensures that the pond has continued access to oxygen throughout the winter. The open water also helps provide a protected area for waterfowl.
Photo courtesy: Aqua Control

There are several types of aerators, and choosing the right one depends on the specifications of the pond itself, the conditions you are treating, and the aesthetic look the homeowner desires. “You need to take a variety of factors into account when you’re deciding on equipment and design,” says Jerry Goldberg, vice president of marketing and sales for AquaMaster Fountains and Aerators in Kiel, Wisconsin. “These include the surface area, depth, shape, present water quality, and water source. You also need to factor in the environment the pond is in and the run-off that affects it.”

Another important factor to consider is what the pond will be used for. Is it a fish pond or a swimming pond, or is it just for decoration? “You have to pay attention to the goal of your clients,” says Goldberg. “Are they primarily looking for the aesthetics of a floating fountain, or are they looking for water quality improvement?”

Photo courtesy: Aqua Master

For clients who are looking for form as well as function, a floating fountain aerator can offer the best of both worlds. Floating fountain systems float on the surface and provide a fountain display in addition to aeration. Display aerators offer a wide variety of spray patterns from subtle to majestic. They add curb appeal and charm to the landscape while helping to improve pond health.

Floating surface aerators also float on top but agitate the surface with a boiling effect instead of providing a display pattern. These are an excellent choice where clients prefer a low-profile aerator.

Aspiring aerators blow oxygenated bubbles into the water, either from the surface down or from the bottom up. If they are strong enough, the oxygenated water may penetrate to a considerable depth, thus counteracting stratification as well as oxygen depletion.

Bottom circulating aerators are completely submerged and cause no break in the surface. They look like large canons that pull water in at one end and push it out at the other. This movement oxygenates the water horizontally.

Photo courtesy: Kasco Marine

Compressed air systems are shore-mounted units that pump oxygen into the water through tubing. These have the capability to cover large areas economically, while not disturbing the natural aquatic landscape.

Choosing the right aerator for the application is obviously critical. “For example, if a pond has a severe algae problem, you need to look beyond aesthetics,” says Bob Robinson, fisheries biologist and director of sales and marketing for Kasko Marine in Prescott, Wisconsin. “A fountain isn’t the most efficient aerator for water quality management. A lot of the energy they use is going into the spray pattern instead of into efficient aeration.”

Angela Hopko of Otterbine Barebo in Emmaus, Pennsylvania agrees. “In general, the more decorative the pattern, the less aeration they’re producing.” This doesn’t mean that consumers shouldn’t choose display aerators in cases where water quality is an issue. Instead, it means that they may need to add more units or use a combination of systems.

Photo courtesy: Aqua Control

Aerator placement is also important. “If the pond is round it makes sense to aerate in the center,” says Hopko. “But if the pond is irregular or kidney shaped, you need to pay attention to the danger areas. In a kidney shaped pond, if you put the aerator in the middle, there will be dead zones. It would be better to place one unit at each lobe.”

Working closely with manufacturers’ specifications and your distributor will help you choose the best system and work some of the bugs out before installation. “Get your local distributor involved in the design process,” says Hopko. “They can troubleshoot things like electrical placement, pond depth, and other factors that will help ensure success.”

An aeration system is an investment, sometimes a big one. But it can protect an even bigger investment by ensuring a long and healthy life for the pond.