Most wavemakers are power strips that alternate power to power heads (submersable pumps) to create 'waves' in your tank to keep things stirred up. Dead spots, or areas in your tank with little or no water flow allow for detrius to build up. By keeping a steady flow of water circulating through the tank, gases are exchanged (O2 and CO2), fish and corals are happier as you simulate a more natural environment (the ocean constantly moves), and dead spots are minimized.
As far as I know Maxi-Jet Power heads are the only recommended powerheads for most wavemakers.
For those considering PowerSweeps:
IMOE Powerssweeps don't last very long as wavemakers so don't waste your money. They are ok to move water, just don't expect them to 'sweep' for very long. I have two of the 228's and have gutted one and the other has become frozen in place regardless of how often/well I clean it.
HTH