Pond Boss Forums AERATION Should I aerate? windmill to aerate or to pump water

It's been awhile since I've posted, but I have been kicking around the idea of a windmill on my 3/4 acre pond with a max depth of 12' depth. My pond fluctuates in height depending on rain (not sure if I'm loosing any to saturation vs evaporation). I would like to be able to keep the pond fuller depending on how much I can get it to pump, but am I better off with a aeration setup and let the pond loose water. or go with a windmill water pump with a solar aeration. I guess I am not sure if a windmill pump will actually be able to keep it full or if I should just get a regular well dug with electric pump to help keep it full. thanks

If you have electric on the property I think you will be spending less $$ with better results with electric aeration and water pump. You can have the pump hooked to a float switch that will keep the pond at the same water level.

A client had a winterkill with a windmill aeration system in one of his ponds while his other ponds with electric (grid) aeration systems did not experience a winterkill.

what actually causes a winter kill, the local hatchery said they have not had a problem with pond turnovers or kills with windmills, whether or not they are feeding me a line (lol) I don't know. at what point do I need to be concerned with water level I am probably about 2-3 feet below normal height right now but it will be full again by end of winter or spring.

From Texas A&M University:

Dissolved Oxygen
Dissolved oxygen is probably the single most important water quality factor that pond managers need to understand. Oxygen dissolves in water at very low concentrations. Our atmosphere is 20% oxygen or 200,000 ppm but seldom will a pond have more than 10 ppm oxygen dissolved in its’ water. Dissolved oxygen concentrations below 3 ppm stress most warmwater species of fish and concentrations below 2 ppm will kill some species. Often fish that have been stressed by dissolved oxygen concentrations in the range of 2 or 3 ppm will become susceptible to disease.

Oxygen dissolves into water from two sources: the atmosphere and from plants in the water. The primary source of oxygen for a pond is from microscopic algae (phytoplankton) or submerged plants. In the presence of sunlight, these produce oxygen through photosynthesis and release this oxygen into the pond water. At night and on very cloudy days, algae and submerged plants remove oxygen from the water for respiration. During daylight hours plants normally produce more oxygen than they consume, thus providing oxygen for the fish and other organisms in the pond.

Oxygen depletions are the most common cause of fish kills in ponds. Most oxygen deletions occur in the summer months because 1) warm water holds less dissolved oxygen than cool or cold water, and 2) because the pond’s oxygen demand is greater in warm water than in cold water. Fish kills from oxygen depletions can range from “partial” to “total”. In a partial kill the dissolved oxygen level gets low enough to suffocate sensitive species and large fish, but many small fish and hardy species survive. Most oxygen depletions cause partial fish kills; total fish kills are relatively rare in recreational ponds except for those with extremely high fish populations (>1,000 pounds/acre). The following are descriptions of the most common types of oxygen depletions.

Excessive Phytoplankton
The abundance of planktonic algae (very green water) in a pond is generally related to the amount of nutrients present in the water. Nutrients can wash into the pond from woods, pastures, fields, human activities in the watershed, or come from pond fertilization. Generally, the more nutrients, the more planktonic algae (or other aquatic plants) will grow or bloom. Although phytoplankton is good from an abundance of natural food and oxygen producing standpoint, it can become too abundant or excessive. When phytoplankton become so abundant that water visibility is limited to less than 12 inches there is a danger of an oxygen depletion. These heavy or dense blooms use large amounts of dissolved oxygen at night and on very cloudy/overcast, windless days causing an oxygen depletion and fish kill. This problem is often a consequence of overfertilizing, overfeeding, or excessive nutrients from livestock, fields, or septic lines.

Phytoplankton Die-off
Phytoplankton populations, or blooms, can grow rapidly, particularly on sunny days when the water is warm and nutrients are available. Alternatively, they can die-off quickly, especially in the spring and fall as water temperatures change rapidly with weather fronts. However, a bloom die-off can occur at any time of the year with little or no warning.

Typically during a bloom die-off, the color of the water will start to change. Leading up to a bloom die-off the pond water may have a “streaky” appearance. Streaks of brown or gray-black through the otherwise green water of the pond is an indication that the algae are starting to die. As the die-off progresses, the whole pond will turn from green to gray, brown, or clear. The pond water will typically clear after a die-off as the dead algae settle to the bottom.

Plankton die-offs cause rapid oxygen depletions for two reasons: 1) the remaining dissolved oxygen is consumed by aerobic bacteria and fungi in the process of decaying the dead algae and 2) few live phytoplankton remain to produce more oxygen. Secchi disks can be used to monitor bloom densities. Any bloom that reduces visibility in the pond to 12 inches or less may cause oxygen problems.


In the winter, the build-up of snow on the ice limits the amount of sunlight that reaches the water. Using an aerator to keep the pond open does three things. 1) allows decomposing gasses to escape the pond 2) allows sunlight into the pond 3) allows water to absorb oxygen from the air.

While windmills do a fine job aerating a pond when there is wind, they stop aerating a pond when there is little or no wind. My client had a winterkill when the wind was minimal for a 2 week period, and also during that period there was heavy cloud cover/fog that limited the amount of sun that reached the pond. The temp dropped enough so that the open water froze, and we had a couple inches of snow fall during that time too. Many things contributed to the winterkill that year in that pond. The drop in sunlight probably also resulted in a phytoplankton die-off which was another nail in the coffin.

For ponds where there is no electricity, and solar is not an option, then the only option is a windmill, and to keep tabs on the biochemical demand in the pond. But, I never recommend a windmill when there is electric on the property.

Ask the hatchery how many pounds of fish per acre of water they carry over the winter in the ponds that they have aerated with a windmill, and if they use any other type of aeration during the winter other than a windmill if the wind stops.

I've got electric about 150 feet away, thought about mounting a pump in the barn and running the air hose out to it. I just didn;t know how much my electric bill would go up.

Here ya go!

http://www.vertexwaterfeatures.com/aeration/aeration-electrical-running-costs