Many chemical parameters are determined as the difference, d, between two measured values, designated as larger (g) and lower (w) inputs, (d = g – w; where g > w) determined from independent measurements such as:   Magnesium Hardness (mg/L of CaC03) = Total Hardness – Calcium Hardness Chromium (III) = Total Chromium – Chromium (VI)   The uncertainty associated with Read more about Managing the uncertainty and limit of quantification of parameters determined by the difference between independently measured values[…]