Jack, 
 
If the sand you are referring to is the stuff from my LR tank, then those are definitely baby snails.  I have tons of them in my 20G - some are reaching about 6-7mm in diameter (foot).  They will continue to grow in your refugium... 
 
Ryland 
		
	
		
		
		
		
			
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				Funny, I don\'t remember being absent minded...
			 
		
		
		
		
	
		
		
	
	
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