ppm
 

Various test equipment lists 'ppm (mg/L)'. This does not make any sense to
me since this is mixing a weight with a volume UNLESS one milliliter of
water (or some substance) weighs one gram. 1000 milligrams x 1000
milliliters=1,000,000 mg per liter. Is this true? While I'm at it: does
one ounce of water weigh one ounce?
Bill