Leave the closed loop.  get two powerheads + wavemaker to intermitantly break the linear flow at the sides of the tank - use the PHs to push against the flow. 
		
	
		
		
		
		
			
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				bye for now, Kim. 
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for every vision... 
there is an equal and opposite revision.
			 
		
		
		
		
	
		
		
	
	
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