Water circulation is the heart of any aquaponics system. The pump moves water from the fish tank or sump through the grow beds and back again.
A common rule of thumb in aquaponics is to circulate the full volume of the fish tank roughly once per hour. This ensures fish waste is moved to the filtration or grow beds where bacteria can convert it into nutrients for plants.
For example, if the fish tank holds 300 gallons, a pump capable of moving around 300 gallons per hour after head loss is usually sufficient.
Head height must also be considered when choosing a pump. Head height refers to how far the pump must lift water vertically. The higher the water must travel, the more the pump’s flow rate will decrease.
Manufacturers provide pump curves that show how flow changes with increasing head height. Always check the expected flow at the actual height your system requires.
It is usually better to slightly oversize a pump rather than choose one that barely meets the requirement. Flow can be reduced with valves if necessary.
Energy efficiency is another factor for systems that run continuously. Many aquaponics growers choose submersible pumps designed for ponds or hydroponic systems because they are built for long operating hours.
Selecting the right pump ensures consistent water movement, proper filtration, and healthy conditions for both fish and plants.