The addition of an aeration system is one of the greatest biological benefits you can provide for your lake or pond. Diffused aerators and surface aerators are the most common types of aeration systems.
Bottom aeration systems infuse oxygen into the water through compressors. When the aeration system is set up, the compressor forces the oxygen through weighted tubing that connects to porous diffusers which are placed on the bottom of the lake or pond. As air is forced through the diffuser, tiny air bubbles causes the water column to rise.
As the oxygen makes it way up the various thermoclines, the water in these layers mix together. This process is known as destratification. Lakes naturally stratify or separate with thermoclines, meaning they get colder and store less oxygen the farther away from the sun and wind at the surface. Diffused aeration systems are very effective at destratification, and are most commonly used in ponds or lakes with depths greater than 8 feet.
Surface aerators float on the surface of the pond or lake and pull in water, forcing the oxygen-rich surface air to the end of a tube a few feet below the waterline. Surface aerators do not have the total water column penetration that diffused aeration systems have, but does circulate the pond or lake's water more than a standard floating fountain. These are common in smaller ponds or lakes. Surface aerator systems do provide some aesthetic benefit as they come in a variety of patterns and light options.