Vertical pump aerator with ring float
Plastic paddlewheel aerators are relatively inexpensive and are frequently used in the marine shrimp industry to aerate and circulate water in small, heavily stocked ponds. Plastic pontoons support a 1 to 2 hp electric motor which drives 2 or 4 plastic paddlewheels on a steel shaft. These devices do not transfer oxygen efficiently into the water. However, they do provide a reasonable amount of horizontal water circulation especially when used continuously in small, shallow (less than 8 feet deep) ponds. Paddlewheel aerators will not de-stratify ponds by mixing water vertically. Plastic paddlewheels are lightweight and relatively easy to assemble and install in ponds. In the past, the electric motors have not been reliable and have required replacement in some models.
Plastic paddlewheel aerator
Steel paddlewheel aerators are primarily used on large, shallow aquaculture ponds. These aerators are rated from 1/2 to 20 hp and may be well suited for use in ponds where there is minimal need for vertical water de-stratification of depths greater than 10 feet. An electric motor drives a steel spindle with the attached blades arranged in a whorl pattern. The spindle and motor is housed in a metal frame. The aerators' frame rests on two aluminum pontoons and is anchored to the pond bank by steel arms. A high rate of oxygen transfer (Tucker 2005) and plenty of horizontal water movement is provided by these units. Water is pushed from only a few inches below the waters' surface providing little de-stratification of the water column. Although continuous operation is an option, typically these devices are timer or manually activated to run during the night, or as needed in emergency situations. Steel paddlewheels are durable and should provide years of service. They are more expensive than most other aerators.
Steel paddlewheel aerator
Pond fountains consist of a series of nozzles that are supported by a float device and are fed water via a submerged electric pump. When compared to a vertical pump aerator, relatively small volumes of water are sprayed under high pressure into the air for aesthetic purposes. Some fountain pumps may be positioned near the pond bottom to provide some degree of water column de-stratification. Fountains will not typically provide an energy efficient or practical source or aeration/water de-stratification in most ponds.