I would add a damsel and monitor amonia nitrate and nitrites... later you can catch the damsel or leave it in... I personally like my damsels.... 
 
Alternatively, put little pieces of food to strat the cycle... you HAVE to make sure that the cycle is complete.... 
 
As Marlin65 suggested, give it a month or so before stocking it....  
 
I have a Biocube29 myself and I love it!!! harder to maintain thou than the bigger tanks... 
		
	
		
		
		
		
		
	
		
		
	
	
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