VISOCOLOR® HE Carbonate Hardness C20 • Titrimetric determination of carbonate hardness (p/m Alkalinity) • The determination is preformed as titration with hydrochloric acid against a mixed indicator, which changes colour at pH 4.5. (Reaction principle analogous to DIN EN ISO 9963-1 C2 and C24) • Type: high sensitive titration kit • Range: syringe is sufficient for the determination of 0.5 - 20 °d or 0.2 – 7 mmol/l H+ (corresponds to 10 – 350 mg/l CaCO3) 1 gradation mark = 0.5 °d = 0.2 mmol/l H+ • Sufficient for about: 200 tests with an average carbonate hardness of 10 °d or 4 mmol/l H+ • Shelf life at least: 2 years • Sea water suitability: yes • Detectable with PF-11: no • Carbonate hardness is that portion of calcium and magnesium ions which are present as carbonate or hydrogen carbonate. • Normally the carbonate hardness is smaller than the total hardness. • If the carbonate hardness is larger than the total hardness, you should trace the origin of this abnormal conditions, e. g. discharge of alkali hydrogen carbonates or high buffer capacity.