in my experience you're going to get some hair algae. sometimes a lot depending on how your rock is to begin with. 
 
with time (and this means months sometimes) you can beat it by encouraging a lower nutrient environment. I still have a bit too but it's no reason to scrap the rock. 
		
	
		
		
		
		
			
		
		
		
		
	
		
		
	
	
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