Turbulent water movement appears to be an important requirement for many species of sessile invertebrates (invertebrates unable to move about the tank, such as corals and sponges) and seems to be enjoyed by certain fish. Not only do various water currents help circulate food for filter feeding corals, but the change also helps guard against dead areas and causes gentle movement of coral, making them more enjoyable to view.
Wavemakers are devices that allow automatic switching between two or more pumps, producing a pulsed flow. This helps simulate the surge and flow of tidal currents found on a natural reef. Wavemakers provide the ability to design a custom flow for your reef by being able to vary the time each pump runs. Some even have automatic schedule programming to create "calmer seas" at night.
Powerheads are the most commonly used pumps with wavemakers. They can be chosen specifically for the flow rate best for their position, are compact, and do not give off as much heat as regular water pumps.
If you plan to use a wavemaker in your reef tank, you will need a sufficient number of electrical outlets near the tank to accommodate multiple power cords. For safety's sake, use
GFCI (ground fault circuit interrupter) outlets that are designed for safe operation in wet areas.