What Does a Powerhead Do in an Aquarium?
By definition, a powerhead is a small AC-powered centrifugal pump with an inlet and outlet that is designed to move water from one place to the next. As hobbyists, we use this term loosely to also include propeller and gyre-style pumps (wave pumps) as well. There really is an incredible variety of "powerheads" available to aquarists and they have a number of useful applications in and around an aquarium.
Utility Pump Powerheads
These are just small, inexpensive water pumps that push a concentrated or focused stream of water, usually designed to move water from one place to the next. The small nozzle easily attaches to flexible tubing but can also accept a variety of accessories and nozzles depending on the particular application.
Common uses for utility pumps:
- Push water into filtration equipment like media & algae reactors, refugiums, turf scrubbers, kalkwasser stirrers, and UV sterilizers.
- Mixe saltwater using synthetic sea salt
- Move water in/out of the tank during water changes
- Aeration (primarily freshwater tanks)
- Breaking surface tension to improve gas exchange
- Vacuuming and blowing detritus from hard to reach areas of the sump and aquascape
- Return pumps in AIO nano tanks
The one application where small utility pumps are not the best choice is for internal flow in a reef tank containing corals. This is because the centralized flow just doesn't move the volume or provide a large enough spread of water movement that is sufficient for a healthy reef tank. The focused stream is just too harsh on the corals as it exits the pumps and the flow dissipates too quickly as it travels into the water column so it won't have the desired effect.
Powerheads For Internal Flow - Gyre Pumps & Propeller Pumps
Propeller and gyre-style pumps have been developed specifically for this application of moving water inside a reef tank with corals and will help to create a much more natural type of water movement in the aquarium. These pumps push a gentler and often wider stream of flow, and in many cases are controllable which allows hobbyists to randomize the flow, create waves, and stir up waste as desired.
Wave pumps like this come in a variety of different styles, each with its own unique features, flow pattern, and control options. They are more expensive compared to your classic utility pumps too but play a vital role in the health of your reef tank.
Internal water flow is important because:
- Delivers food and nutrients to corals and fish
- Stirs up fish waste and leftover food for removal via filtration
- Helps export chemicals and waste that is excreted by corals
- Improves gas exchange and breaks the surface tension
- Creates natural "ocean-like" currents in the aquarium