How are the hinges on your refractometer?  If they are at all stiff….don’t swing very easily….you are getting a false reading.   Stiff hinges will cause for a false low reading (resulting in higher salinity then what the refractometer says.)  If you are a constant recalibrater, you will be compensating for the false reading.   However, with a little maintenance, your refractometer will be humming smoothly.
 
What I do to lube the hinges is to first squirt a little WD-40 into an aperitif glass, and then use a toothpick to carefully apply the WD-40 to the hinges only. Even it you get a little spread elsewhere, no big deal. Just use a tissue to wipe it clear. Make sure you get all four hinge points. I then swing the hinge back a forth a few times to free it up and get the lube into the hinge. Once you lube your refractometer, you will need to recalibrate.
 
	
	
	
		
		
		
			
		
		
	
	
		
	
	
		
			
		
		
	
			
			What I do to lube the hinges is to first squirt a little WD-40 into an aperitif glass, and then use a toothpick to carefully apply the WD-40 to the hinges only. Even it you get a little spread elsewhere, no big deal. Just use a tissue to wipe it clear. Make sure you get all four hinge points. I then swing the hinge back a forth a few times to free it up and get the lube into the hinge. Once you lube your refractometer, you will need to recalibrate.
	
					
				
