If you're patient, your live rock will indeed seed your sandbed and eventually your sand will be filled with life. I never added a grain of "live" sand to my tank. Just bags of dry aragonite. After a few months my sandbed was already filled with bugs and worms. Good luck! 
		
	
		
		
		
		
			
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				-Mason
			 
		
		
		
		
	
		
		
	
	
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