Fishing Pond Aeration

What is Aeration?

Aeration is the process of adding oxygen to water with the goal of increasing the dissolved oxygen level of the water. Healthy dissolved oxygen levels are important in order to keep ponds healthy, clean and provide an optimal environment for fish. Fishing pond aeration systems typically fall into two categories: Surface aerators and bottom-up aerators.

Why you should Aerate your Pond

Fish require adequate dissolved oxygen levels in order to live and thrive. Ponds also contain bacteria that break down organic waste and matter which reduces the amount of muck and sludge that settles to the bottom ponds.  Healthy dissolved oxygen levels support improved growth in fish, better water quality and Phosphorus removal which reduces algae. Ponds that have low oxygen levels can be subject to algae blooms, odor problems and fish kill.

Surface Aeration

The two most common types of surface aeration systems are fountains and bubblers. These types of aerators work by agitating the surface of the water which mixes the top layer of the water with the air above the pond. Fountains pump water into the air where the droplets mix with the atmosphere and return to the pond water. Bubblers (or jets) move air from the atmosphere into the surface layer of the pond.

Surface aeration is great for controlling the top layer of weeds and algae. They provide higher levels of oxygen and mixing on the top depths of the pond. The shortcoming of surface aeration is that it does not promote mixing or add oxygen at lower depths. The lower depths of a pond typically are colder and contain less oxygen. Using only surface aeration can lead to a situation called “Stratification” where the environmental conditions are different at various depths. When stratification occurs, the fish will tend to hang out near the surface where there is more oxygen and warmer temperatures. If there is a sudden weather event that mixes the stratified pond  layers, the overall oxygen levels of the pond can lower and cause fish kills.

Bottom-Up Aeration

Bottom-up Aeration systems work by compressing air and delivering it into the water through diffusers installed on the bottom of a pond.  Small bubbles are introduced at the bottom of the pond, and rise up the water column. As they do, oxygen is transferred across the surface of the tiny bubbles and into the water. This provides oxygen and mixing from the bottom of the pond, up to the top regardless of the depth of the water.

Mixing and providing oxygen from the bottom reduces stratification of both temperature and dissolved oxygen levels. Having more consistent oxygen levels at all depths minimizes the risk of fish kill. Another benefit of providing oxygen at the bottom of a pond is that it will support the bacteria that will consume decaying organic matter. Supporting these bacteria will result in cleaner water, better color of water, less muck and sludge, and also keeps algae and weeds at bay.

The main issues with bottom-up aeration is that it is typically a little more labor intensive to install, the diffusers can become fouled and may need cleaning from time to time and they do not agitate the surface of the water quite as effectively as surface aeration systems.