I'll add this; 
No submersible aquarium heater I've ever seen is 'totally' waterproof, besides titanium, and even some of them are not 
  
I keep my heaters verticle and the seals out of the water ... 
Only the glass is in the water and the control heads are dry 
  
I have a couple of old Jager heaters that have moisture inside, so nothing is totally 'waterproof' 
		
	
		
		
		
		
			
		
		
		
		
	
		
		
	
	
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