As you drive around the Tri-County, you will notice that we have a lot of ponds. We use these ponds for a variety of reasons, some of which include fishing, swimming and watering livestock. Fish need a habitat that provides optimum conditions for growth and reproduction. Understanding recreational pond management, water quality, fish introduction techniques and pond aeration can enhance the productivity and beauty of your pond. One of the questions I get a lot is “Do I need and aerator?”

Many pond owners may not know why they might need and aerator. Why would you need one? When fish push water through their gills, they utilize dissolved oxygen (DO) to breath. They do not need very much DO, but if it falls below critical levels (below 2 mg/L), you could have a fish kill. There are three ways that dissolved oxygen is added to a pond: direct diffusion from the atmosphere, wind and waves and photosynthesis, of which photosynthesis is the most important (UF/IFAS #FA27). An aerator is a great way to mimic wind and waves and can increase the amount of DO in your pond.

Dissolved oxygen concentration in a pond changes constantly and this is referred to as the diurnal oxygen cycle. The lowest concentration of dissolved oxygen would occur during the earliest hours of the morning and the highest during the late afternoon. Therefore, DO concentrations could be at their lowest level just before dawn. If dissolved oxygen concentrations are adequate you may not need an aerator; many pond owners never have an issue. However, if your DO drops to critical levels having an emergency plan to add oxygen to the water could help prevent problems from occurring.

Types of aerators

There are many different types of aerators available to pond owners. Some are PTO-driven on tractors while others are electric and are set to run during specific times of the day. Common types of aerators include: paddlewheel aerators, pump-sprayer aerators, vertical pump aerators and diffusers or bubblers. Each of these aerators would be used for specific reasons such as cost, labor, and efficiency.

If you are interested in learning more about pond aeration, management, or other agriculture issues, contact the UF/IFAS Extension, St. Johns County office at 904-209-0430 or by email at timwilson@ufl.edu.

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