How to Aerate a Pond

How to Aerate a Pond

How to Aerate a Pond or Lake

Surface Aeration

The most common type of aeration is surface aeration. Surface aeration is also often aesthetic, that is, if you use pond fountains. Typically, the pump is attached to a float so that the nozzle rises and lowers with the water level. The pump agitates the water below, decreasing stratification (layering of water). In addition, water is forced into the air so that the pond’s water is always being recirculated.

There are two common kinds of fountains used for surface aeration. Also, you can choose pure surface aeration with no display whatsoever.

The use of decorative pond fountains provide the versatile patterns and typically (not always) include multiple nozzles to change displays when you wish. The catch is that to provide so much display, nozzles can be intricate with many holes, and pump impellers are used. Fewer gallons per minutes of water are the result. The use of nozzles restricts flow and therefore less aeration occurs. Because of this, Kasco Marine recommends using a 1HP pump for every ½ acre of surface area (a 100 x 200’ pond approximately). It should be noted that Kasco biologists and engineers make recommendations according to optimal pond health, and sometimes less HP works well enough. Also note that this ratio is for Kasco fountains. Some companies provide very tall or very wide displays, but to get that water so high the nozzles are restricting quite a bit of flow. If you see a one-half horsepower unit pushing the water 40 feet into the air it is doing so by restricting the outflow of the pump, decreasing the aerating properties.


Aerating Surface Fountains

Aerating Fountains provide only one kind of display, the V-pattern. It’s not so much a nozzle at the top, usually, but an open vent. The flow is not restricted by an intricate nozzle and the pump uses a propeller rather than an impeller. Kasco recommends 1 ½ HP of fountain for every surface acre of water (a 200’ x 220’ pond). Of course how much HP you need depends on the manufacturer of the unit you eventually purchase. And Kasco is always recommending for optimal pond health; you can still increase your pond health with smaller units.

Surface Aerators without Display

Surface aerators are only that, aerators. The pic above might appear to be decorative, and with lights added it would be. But it is 5HP! A propeller is used without a nozzle of any kind. Kasco recommends a 1HP to 1 acre ratio  (that is, 1 HP for every 200 x 220’ of pond). Of course, this varies with manufacturer and shape of pond.

Bottom Aeration

For very deep ponds (over 7’ or 8’), bottom aeration is recommended. Typically, an air compressor is located at the shore and a hose carries the air to a diffuser unit at the bottom of the pond. It is very similar to the air bubbles rising from the bottom of an aquarium.  Currently, there are many fairly quiet air compressors available for sale. They need to be housed to protect from the elements, thus quieting them more.These also use less electrical energy than do pond fountains.

Combining the Two Types of Aeration

If you have a deep pond but still want to see a fountain, you can combine the two types of aerators. The fountain would not need to aerate as much and could focus on beauty. This focus allows for a greater range of price as well as dramatic viewpoint.

Solar Aeration

Solar aeration is an option and could be explored by you. We get many calls about solar aeration. The goal is to eliminate the necessity of wire going to an electrical junction. While we are entirely sympathetic, these units are typically quite expensive, so don’t be alarmed by an approximately $8,000 price tag for a 1/2HP unit. Also, they don’t normally include batteries, so they run when the sun is out unless also attached to the grid. For smaller backyards ponds, solar units, of course, are much less expensive, ranging normally between one hundred to three hundred dollars for the panels and the special pump to be used with solar. Often you can add battery packs to these. However, we ourselves have had limited success with battery packs, and when we recently conducted an online customer review of the batteries that go with these, we found very mixed reactions. Just be careful and do your research.

Windmill aeration

Wind units are pretty to look at, but installation time is lengthy, and you need to find the best point to install right off the bat, as moving windmills takes too much time. In addition, these do not turn when there is no wind, and when there is no wind rippling across the pond surface is the same time you need more aeration. If it is windy outside, your pond surface is already being churned by the wind.

An excellent investment for your home or property is installing a pond that looks right. The benefits are unquestionable. Some people chose for beauty, while others want their homes to have a relaxation point as a lifestyle goal. A fountain for your pond is an enjoyable asset as well. But it’s not only the beauty that they add but also the necessary aeration to keep your pond life heathy.


Bacteria are all around us. They are necessary and good but can also be unhealthy and detrimental. When it comes to ponds, it is important to think about the differences between aerobic and anaerobic bacteria.

Anaerobic bacteria live in the unoxygenated parts of the pond. These bacteria digest unwanted organic debris but release a stinky gas. They also digest the unwanted debris more slowly than aerobic bacteria. Thus, plant material and fish wastes build up at the bottom of the pond and accumulate into muck. Your pond can soon become unhealthy.

Aerobic bacteria thrive in the oxygenated parts of the pond. These bacteria digest the unwanted organic debris faster than anaerobic bacteria and make for a much healthier pond. The pathway to a healthy pond and to keep it clearer is to circulate the layers of the pond and spread aerobic bacteria throughout.

An aerated pond is a happy pond

Aeration is important to prevent your pond from going into an anaerobic state. Aerobic bacteria thrive, which create a harmless gas as they eat away at unwanted pond debris. You don’t get the rotten egg smell. In addition, aeration mixes the warmer surface water with the colder, deeper water. As the water is churned, the temperature of the pond will be more consistent throughout. Algae will be decreased.

You Can Also Add Beneficial Bacteria

On top of aeration, you can add beneficial bacteria to your pond or tank to eliminate sludge and foul odors. There are several products on the market. Kasco Macro-Zyme contains a high concentration of facultative anaerobic bacteria that will rapidly reproduce and consume organic material in your pond or lake. It is easy to use and releases billions of beneficial bacteria & enzymes that work around the clock to clean, neutralize, and purify. Application is simple and it is SAFE for HUMANS., PLANTS, and ANIMALS.

 Fish Need Oxygen

Just like us humans, fish need oxygen to survive; they just get their supplies underwater. Aeration keeps pumping fresh oxygen into the pond, preventing or decreasing the risk of fish kill, when a whole lot of fish die at the same time. Oxygen is dissolved more consistently throughout the pond, rather than in layers.

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