VISOCOLOR® ECO Carbonate hardness • Titrimetric determination of carbonate hardness • The determination is preformed as titration with hydrochloric acid against a mixed indicator, which changes colour at pH 4.5. (Reaction basis according to, DIN EN ISO 9963-1 C24) Type: titration test Range: 1 drop = 1 °d Sufficient for about: 100 tests with an average hardness of 10 °d Shelf life at least: 2 years Sea water suitability: yes Detectable with PF-12: 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.