Magnesium is the third most abundant ion in seawater, surpassed only by sodium and chloride. Its abundance is critical in the formation of weak ion pairs with carbonate ions. This allows calcium and carbonate ions to be available for uptake by corals and invertebrates. Low levels of magnesium lead to low or unstable levels of calcium and alkalinity. Signs of lowmagnesium levels include precipitation of calcium as insoluble calcium carbonate and impaired inhabitant growth and health.
Range: 1000 to 1800 ppm Magnesium
Resolution: 5 ppm
Accuracy: ±5% of reading @ 25 °C (77 °F)
Light source: Light Emitting Diode @ 610 nm
Light detector: Silicon photocell
Method: Adaptation of the colorimetric EDTA method using calmagite indicator. The reaction between magnesium and the reagents causes a blue to violet tint in the sample.
Environment: 0 to 50 °C (32 to 122 °F); max. 95% RH non-condensing Prepared sample cuvette (sample plus reagents) must be 18 to 28 °C (64 to 82 °F).
Battery type: 1.5V AAA Alkaline
Auto shut-off: After 10 minutes of non-use
Dimensions: 86.0 x 61.0 x 37.5 mm (3.4 x 2.4 x 1.5”)
Weight: 64 g (2.3 oz)
Interferences: Calcium below 300 ppm and above 500 ppm
Ordering Information: HI783 Checker HC is supplied with sample cuvette and cap (2 pcs.), Marine Magnesium reagent starter kit (reagents for 25 tests), 1 mL graduated syringe and tip (1 pc.), 5 mL syringe and tip with black printing (1 pc.), 5 mL syringe and tip with blue printing (1 pc.), 1.5V AAA Alkaline battery (1 pc.), instruction manual, and quick-reference guide.