Glass drill bits are NOT that expensive... see for yourself... http://www.mops.ca/cgi-bin/SoftCart....html?E+scstore
The most expensive one is 20 bucks. I'd drill the back and build an overflow myself    
		
	
		
		
		
		
			
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				Calvin 
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Planning a 29 gallon mixed reef...
			 
		
		
		
		
	
		
		
	
	
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