A diffused air system is a shore-mounted unit that pumps compressed air to diffuser plates located on the bottom of the pond. This method circulates the entire water body, which eliminates stratification and aerates all of the water in the pond. Fountains (or fountain aeration) are located on the surface of the pond, with an intake that only draws from the top few feet of water. This does not eliminate stratification and only mixes a fraction of the water column.