I can vouch for the Rena Air 400, using one on my air diffuser skimmer, although my system & skimmer are a tad smaller than yours. It has two outlets, both controllable, I run it wide open & it's quiet. Using a single large self made basswood air diffuser and I run the two lines into one with air check valves. 
		
	
		
		
		
		
			
		
		
		
		
	
		
		
	
	
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