Look into running your system as a 'Herbie' 
The 1" will be your main drain 
The 3/4" will be your emergency drain 
  
Then you need to plumb over the back for your returns 
  
Look through the first, I don't know, maybe 10 pages, of my build thread for some pics etc 
  
Link is my sig 
		
	
		
		
		
		
			
		
		
		
		
	
		
		
	
	
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