Hanna Instruments Hanna Core Parameters Kit (772 Alk, 758 Calcium, 783 Magnesium) Checker HC (Saltwater) - Hanna Instruments $191.85 772 CheckerThe HI772 Checker®HC (Handheld Colorimeter) provides a simple, accurate and cost effective way to measure alkalinity in degrees of calcium hardness, commonly abbreviated as dKH. Critical to marine environments, alkalinity not only provides... Add to Cart