Does not suffer from calcium and strontium interferences when within certain bounds.
Calcium alone cannot form the skeletal material of corals and allow calcareous algae to grow. Some other substances are needed as well. A few other constituents are carbonate and bicarbonate. These two substances also have a major impact on the stabilisation of the pH in the proper range of 8.1 – 8.4. Such stabilisation is also called buffering.
The total carbonate and bicarbonate concentration is also called carbonate alkalinity or carbonate hardness. The only difference between alkalinity and carbonate hardness is a conversion factor.
Natural seawater has an alkalinity of approx. 2.7 meq/L or approx. 7.5 dKH when expressed as carbonate hardness.
For a stable system the alkalinity or carbonate hardness should have a value similar to natural seawater or slightly higher and should preferably not fluctuate by more than 5%. This means a maximum fluctuation of 0.14 meq/L or 0.4 dKH.
Therefore an alkalinity test kit should be capable in measuring in steps smaller than 0.14 meq/L.
The Salifert KH/Alk test is very straightforward. It measures in sufficient small steps of 0.1 meq/L or 0.3 dKH with a sharp color change. This makes detection of important yet small change possible.
The kit can perform approx. 100 - 200 measurements.