Paddle wheel aerators are commonly used in semi-intensive shrimp/prawn culture and is one of the major capital cost item in the farm. The paddlewheel aerators are used to increase contact surface of water with air thereby increasing the area through which oxygen is absorbed by the water and to create a circular movement of the pond water. This has the following advantages:
It increases the dissolved oxygen level of the water and prevents oxygen depletion during the night.
It accelerates the diffusion effect of not only the oxygen, but also enables the capture or release of carbon dioxide. Carbon dioxide is important for culture of algae and therefore for maintenance of appropriate watercolor.
It facilitates the volatilization of undesirable gases such as N2, NH3, CH4 and H2S.
It reduces the daily fluctuation range of pH value.
It accelerates the decomposition and mineralization of organic matter in waterand soil and helps in the release of nutritive value of fertilizers.
It diminishes the possible stratification of pH, DO, salinity and temperature inthe pond water.
It helps in mixing the pond water and maintenance of ideal conditions all overthe pond.
It increases turbidity when necessary.
As the pond water moves in a circular fashion the pond bottom is cleaned and the waste matter gets accumulated in the center and the corners. By this method most of the pond bottom is kept clean.
It is very important during application of chemicals or medical treatment with respect to distribution of chemicals/medicines throughout the pond and ensure to be careful in proper water exchange to reduce any side effects. Use of paddlewheels also has the advantage of accelerating the evaporation rate thereby increasing the salinity. This is however, an advantage in the condition of low salinity.