The airlift works by pumping hundreds of air bubbles into the bottom of a piece of pipe. As the air bubbles rise to the surface, they carry the surrounding water with them, forcing it to move up the pipe to the outlet where it is expelled into the next tank. The second tank, the Waste Recycling tank, is where an often overlooked group of organisms live and work. For example, plants need a lot of nitrogen in order to grow properly. When fish excrete nitrogen into the water, it is excreted in an ammonia molecule.
Ammonia is extremely toxic to both fish and plants.
Fortunately, bacteria exist that can convert ammonia into a more useful and less toxic molecule called nitrate . The Waste Recycling tank is full of micro-organisms that convert waste molecules that flow from the other two tanks into molecules that can be used. Included in this community are bacteria, zooplankton, molds, fungi, and snails and other invertebrates. The third tank in the system is called the Plant Production tank. This tank contains plants that absorb light and convert it into useful molecules for organisms in the downstream tanks.