A Bell auto-siphon is the heart of an Aquaponics system, though it can also be used in an hydroponic setup.

Flood and drain cycling in ebb-and-flow aquaponic systems can be controlled by electronic timers, which regulate the activity of water pumps, or by non-mechanical devices called automatic siphons. These auto-siphons can start and stop water flow on their own, depending on the level of water surrounding them. The bell auto-siphon is one of the simplest methods.