How An Aquarium Pump Works

Keeping the water clean in an aquarium keeps the inhabitants alive and healthy. Circulation and filtration are ways of making sure the water stays healthy and does not become a stagnant pool. Aquarium pumps are used to move the water to the surface, which allows it to interact with the air (aeration). This is important because the interaction provides an opportunity for the release of carbon dioxide (the bad stuff) into the air and the absorption of oxygen (the good stuff) into the water. Carbon dioxide sits below the surface and needs to be stirred up to rise. Aquarium pumps also create circulation which eliminates stagnation.

Air pumps work by displacing the water. Air pulled through the pump creates bubbles when released into the water. Bubbles displace the water, stirring it and sending the carbon dioxide to the surface. External pumps move the air via a hose attached to the pump that is dropped into the water. Water pumps are submersible and work by creating a current, or movement, in the water.

The use of the term "aquarium pump" is a generic reference. Aquarium pumps are also called water pumps, air pumps or powerheads. In the spirit of becoming more efficient, manufacturers have in some models included the pump and filtration system within the same unit. Air pumps are great for smaller tanks (below 50 gallons), providing proper gas exchange but very little circulation. Tanks at 50 gallons or more need a water pump that is submerged into the tank. A water pump does not deliver a strong current but does circulate the water well. Powerheads create strong current and are not appropriate for all fish or environments. Product failures and filter clogs can block aeration and circulation. Having an extra air pump on hand is a good aquarium safety measure.

Aquarium pumps are rated by flow rate and according to the per gallon size of the tank. Matching the size of the tank to the information about the pump is usually the best way to begin choosing a pump. Other items you decide to include in the tank may require a larger pump purchase. Plants and additional items make the need for a larger pump necessary. Choose a pump for a larger tank if the aquarium will be home to other oxygen lovers like plants.