Machete, the return will be going up over the back...I have an SCWD and two u-tubes which will hopefully give me some alternating currents in the tank.  I also have a union for the emergency but wasn't sure whether to use it or not.  If I lower the emergency pipe into the tank as well, I will for sure need to use it. 
 
Fkshiu, thanks for the advice...I don't have any Herbies to readily look at so all advice is appreciated.  I will lower the emergency as you suggested. 
 
Anyone else with some thoughts? 
		
	
		
		
		
		
			
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				Mark...
  
290g Peninsula Display, 425g total volume.  Setup Jan 2013.
			  
		
		
		
		
	
		
		
	
	
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