oxygen enters the water primarily through direct diffusion at the air-water interface and through plant photosynthesis. Because fo the lack of photosynthesis in indoor water recycling oxygen to animals cultured in these systems. In RAS oxygen depletions can be calculated, but as predictions may be misleading, these systems never are available to the fish farmers. the general categories are
paddlewheels
Venturia pumps
Agitators
Liquid oxygen injection
impellers
Airlrft pumps
air diffusers
which aeration should be used depends on the actual environment of the fish farm.