Powerhead (pump)

An aquarium powerhead is typically used to create flow throughout the tank. For example, a single powerhead could be used at one end of a freshwater aquarium to simulate a laminar river current, or multiple powerheads can be positioned throughout the aquarium to create more turbulent flow.^{[citation needed]}

A switching or variable-voltage system (also known as a "wavemaker") is commonly used in reef aquaria to more closely simulate the movement of ocean water.^[1]

Water circulation is vital to proper biological filtration of most saltwater aquaria (particularly those using the Berlin Method), and is useful in freshwater aquaria for allowing free-swimming fish adequate exercise.^[2]