I run 10 stages because I have to not because I want to, my water is 280 ppm out of the tap, like daplatapus said, if your water is less than 50 ppm then a simple 3 or 4 stage unit would suffice. 
		
	
		
		
		
		
			
				__________________ 
				Crap happens, that's why they sell toilet paper in 48 roll packs!
			 
		
		
		
		
	
		
		
	
	
	 |