This came with my craigslist tank. The local fish store folk did not connect it and said I dont really need it, and they werent sure what it was. 
1. What is this?
2. What material is inside? looks like tiny black rods.
3. Can I connect it to the return pump or this will require another pump?
Thanks
								
								
				
			1. What is this?
2. What material is inside? looks like tiny black rods.
3. Can I connect it to the return pump or this will require another pump?
Thanks

 
				

 
			 
 
		 
			
		
	
	
		 
			
		
	
	
		 
			
		
	
	
		 
			
		
	
	
		 
 
		 
			
		
	
	
		 
 
		
