Powerheads are most commonly used to power undergravel filters (UGF) in the aquarium, via uplift tubes. They create a more powerful flow than air-driven uplifts. This increased flow will mean a greater filtration turnover per hour.
In larger aquariums, it is normal to have at least two uplifts, usually in the back corners of the tank, to provide the necessary flow through the gravel.
Powerheads can also be employed without UGF - to create additional circulation, provide additional mechanical filtration with the aid of add-on cartridges, or power additional devices such as fluidised bed filters. In marine aquaria, several powerheads are often used to create the turbulent circulation necessary for many reef tanks, and can be controlled electronically to create different 'wave' patterns.
Good circulation in an aquarium can be important for a number of reasons. One of the most important is to circulate the water from the surface (where it interacts with the air to pick up oxygen) - to the lower levels of the tank to maintain high oxygen levels.
Powerheads are available in a range of sizes to suit different size aquariums and accessories. Some are equipped with a venturi device, which adds a stream of air bubbles to the outgoing flow (but reduces the overall turnover rate). Most have an adjustable output direction, and some have a flow speed control. The fittings also vary on powerheads, so it may be necessary to determine how they will fit into the tank (allowing for any bracing bars) before setting up.
Specifications for specific powerheads can be found in our Equipment Section.