Bottom Aeration

Why do I need to aerate my lake?

Thinking about aerating a large body of water can be daunting, especially when a pond or lake is several acres. The best way to understand “why” is to think about what exactly a lake is. A lake is a giant funnel that is open to everything. A lake catches rain,
fertilizer run-off, bird waste, fish waste, wind-blown organics, and even trash. Left unattended, over time, odor and gases develop from all those harmful environmental inputs rotting at the pond bottom. You can’t vacuum it and you can’t cover it. So, what do you do? The most environmentally friendly and economically sound remedy is to aerate. There are two ways to aerate. You can aerate at the surface with a fountain or a circulator, but that only aerates the top of the water, or you can utilize bottom aeration that aerates the entire water column from the bottom of the lake to the surface.

How does bottom aeration work?

When the compressed air reaches the diffuser a micro-perforated membrane on the diffuser head “diffuses” the air into millions of tiny air bubbles resulting in a giant oxygen column that expands as it rises. As these bubbles rise through the water column,
they de-stratify the different layers of the lake, mixing colder water from the bottom with warmer water of each column. These layers are what is called the thermocline of a lake (different layers of temperature). This process also helps fish become less stressed and greatly reduces the chance of seasonal fish kills.

However, where lake-bed aeration does the majority of its work is the bottom of the lake. Lake bottoms have very little oxygen so dead leaves and organic waste tend to accumulate in layers and rot. As those layers of muck break-down they release harmful gases like ammonia and nitrite which creates a “rotten egg” odor. Aerating that area assists in releasing those gases and helps the natural bacteria population present at the pond bottom grow and digest organics (muck).

You might think that once the bubbles reach the surface that their job is done. Not true. The bubbles on the surface help in two ways. This is where harmful gases from the more anaerobic (lacking oxygen) layers of the lake escape. These include ammonia, nitrite, and nitrate which are detrimental to fish and overall health and clarity of the lake. Additionally, the wave action created by the bubbles breaking the surface also helps keep the water constantly moving. This keeps odor down, prevents stagnation, and
keeps mosquito larvae from proliferating.

Compressor

Compressors are housed in a compressor cabinet near a power source. Compressor cabinets contain a compressor or multiple compressors, an air manifold, cooling fans and connecting airlines.

Weighted Tubing

The weighted tubing delivers air from the compressor to the diffuser at the bottom of the lake. The weight of the tubing keeps it at the bottom of the lake.

Diffusers

Depending on the size of the pond you can have one to multiple diffusers throughout the pond. Diffusers receive the air from the compressor and “diffuse” it into tiny bubbles that aerate the entire water column from the bottom to the surface.

You can purchase a complete aeration kit that contains the amount of airline and diffusers you would need for the installation. These are typically designed for smaller lakes, generally up to 6 acres. For a 6 acre pond you would need 6 diffusers and around 600 feet of airline. Generally speaking, most systems are designed on a 1 diffuser/100 feet of airline per acre layout.
For larger bodies of water or uniquely shaped lakes, different lengths of airline and number of diffusers may be required. Contact your Anjon Sales Representative for consultation