In recirculating aquaculture systems, there should be a constant flow of water and there should be a possibility to alter the speed, pressure, and direction depending on one’s requirement. The movement of water is controlled through gravitation and before it is used in the system, it is generally pumped to an elevation from where it begins to flow.
The most common types of pumps used in RAS is a centrifugal pump which operates from the thrust generated by the spinning of water at a high speed in the pump head. The pump is usually placed outside the tank and operates at high pressure. A pump with high flow, and low lift capacity is chosen to minimize energy consumption. Earlier centrifugal pumps had a recirculating pressure of 25 ft, but now the pressure is about 10ft. two other types of pumping arrangements are axial and airlifts pumps.
