What is the advantage of a wave maker?
•    A wave maker enables you to create more natural flow in the aquarium.
•    A dump bucket wave maker creates the wavelength and intensity of light penetration to alter. This will create a pulse effect that is both desirable and natural.
•    A wave maker can be the make or break for many corals that require inconsistent flow e.g. goniopora, xenia.

How do you make a wave maker?
•    Dump buckets can be created to achieve a wave motion. The way the dump bucket works is a flow of water enters the bucket, which becomes top heavy and tips over, emptying its contents into the tank. It is designed to spring back once it has been emptied because the excess weight that caused it to topple has been expelled and the weight of the remaining water causes it to become up right once again. Be careful because the dump bucket is messy and produces salt spray. A tank with a dump bucket cannot be filled to the top; it must have high sides to stop spillage.
•    The next best thing is to have a set of internal powerheads in the tank set on timers to come on and off at various times. This will create counter currents so the flow is less consistent. It is good to hide the powerheads with rocks so it is out of the direct line of vision as long as the flow is not restricted. (This constant on and off action creates a high amount of wear and tear on the pumps though it is worth it).  
•    Some external types of water pumps are fit with flow regulators that can be altered manually daily to achieve some form of irregularity. 
•    A very simple wave maker is an airline without an air stone it will produce turbulence resulting in small waves. Airline with no air stone causes salt spray.

Good luck & enjoy,

Paul Talbot