2.3.2.4 Pumps
The pumps in our aquaponics system are needed to pump the water from the fish tank to the growing
bed. Choosing the right pump is another important step because it directly impact the system
functioning and the efficiency of the overall system. The two main types of water pumps are Impeller
and air lift pumps. The Impeller pumps are the conventional pumps that use a turbine to push the water.
This pump is most widely used in both backyard aquaponic projects and large commercial systems.
(Figure 22 )
Figure 22. Impeller Pump
This pump is very powerful and very efficient. It does not require a lot of maintenance too. The
main drawback is the possibility of backflow. That occurs for example when the pump is not
working properly the water could flow in the opposite direction ,something that we must avoid in
our system because we want the nutrients for the plants to go from the tank to the growing beds
and not vice versa. Since we need to keep our system biologically safe we need to avoid any oil
leaks from pumps in the water.
Impeller pumps come in various styles, such as inline pumps that connect to piping, or submersible
pumps that sit in the tank.
We also have the airlift pump shown in Figure 23. This kind of pump is powered by air. The air is
pushed inside the cylinder filled with water and the water is lifted due to the air pressure inside the
cylinder. The problem with this kind of pump is the height of pumping water. As we can see from Figure
23 the maximum height we can pump the water is dependent on the fluid level in the main tank. This
really limits the practical uses of this pump.