Learn About Aquarium Air Pumps

Air pumps are generally used in aquariums for three purposes: To power an under gravel filter, to aerate the water, or to power decorations, ornaments and designer air stones.

Air pumps attached to under gravel filter tubes draw water through the gravel bed to trap debris on top of the gravel where you can vacuum it away.

Their use for under gravel filters is necessary. Air is pumped via a slim tube and air stone to the bottom of the aquarium where it creates a tower of air rising back to the surface of the tank. The air takes with it water that comes from underneath the under gravel filter plate. In order for water to get underneath the filter plate, it has to pass through the gravel bed where it is filtered before being drawn up the air tube with the air bubbles, returning to the surface cleaned of debris and particulates.

Air pumps attached to under gravel filter tubes help to keep the tank oxygenated.

Fish must have a nice high oxygen content in the water. The tower of water drawn from under the filter not only filters the water, but also aerates the water when the bubbles reach the surface and agitate the top of the water, increasing the oxygen uptake. (Full hoods on top of aquariums often hinder oxygen exchange. An air pump attached to some type of air stone will draw fresh air from outside the tank into the closed system under the hood.) Air pumps used for aeration also help to reduce the build-up of harmful gasses such as carbon dioxide which can stealthily lower the pH of your tank.

The beneficial bacteria (growing in the gravel bed) that process the water waste also depend on oxygen. Without beneficial bacteria, the water would become concentrated with toxic chemicals.