Water
12. Good quality natural water or reconstituted water (see Annex 2) is preferred, although drinking
water (dechlorinated if necessary) may also be used. Waters with total hardness of between 10 and
250 mg CaC03 per liter, and with a pH 6.0 to 8.5 are preferable. The reagents used for the preparation
of reconstituted water should be of analytical grade and the deionised or distilled water should be of
conductivity equal to or less than 10 μScm-1.