A built-in overflow is the most efficient method of draining aquarium water to a filter. If your aquarium does not have built-in overflow, Continuous Siphon Overflows/Prefilters are the best means for getting water from an aquarium to a filter system without expensive modifications to the tank. They quietly skim up to six times more water than units with tubes.
 
The advantages of Continuous Siphon Overflows/Prefilters include:
	
Adjustable water level allows you to easily change the level in your tank. 
	
Black top reduces algae growth. 
	
Quiet operation.