They work great with smaller tanks. Do not go over the recommended flow rate a they just shift from one side to the other far to fast. I helped some put one in a 72G tank. The tank had a center overflow and we put it in there with flow to each side of the overflow. It worked very well. 
 
Tom R 
		
	
		
		
		
		
			
		
		
		
		
	
		
		
	
	
	 |