I've seen lots of great setups without them.  IMO, they are more harmfull than beneficial.  I was going to buy one myself at one point, but my research on the matter dissueded me.  If you are just getting started, I would recommend priority on a good skimmer, lighting, and circulation above all else.  Rich. 
		
	
		
		
		
		
			
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				90gal Starfire mixed reef, 400W MH (Giesemann 13K megachrome/Icecap E-ballast), (2) 54W T5 Giesemann true actinic, 45gal sump (65W 50/50 PC), ASM G-3 Skimmer, Mak 4 return, Sequence Dart closed loop, foam backdrop, 120 lbs LR, 2" sandbed, & 1 dillhole running the show.
			 
		
		
		
		
	
		
		
	
	
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