MWF Magazine: I enjoyed reading Dom Ruggeri's article on coolant evaluation.  It's good that you have someone who can articulate the subject matter in terms understandable to all who read it.  I only have one small comment.  I have found that many who use the shop refractometer naturally assume that the numbers are equal to percentage of concentration.  This may not be true of different brands of refractometers.  We tell our customers to mix a small measured quantity of the coolant to the concentration they intend to use then take a reading of the sample.  This is the truest yardstick for the coolant they are using and at the concentration they intend to maintain.  I don't mean to be picky and certainly am not criticizing Dom's piece.  I thoroughly enjoy checking the site each week to see what is new.  I tell all we contact about MWF Mag. and suggest they get their "formal" education on coolant at this site.  Keep up the good work.