Determine calcium (Ca) and magnesium (Mg) in water samples for saltwater reef and coral aquarium. This product is specially designed for a reefer who essentially requires measurement of calcium and magnesium in coral aquarium very precisely. The color change during endpoint both Ca (from pink to blue) and Mg (from orange to green) are sharp and contrasting which make results easy to read. It is also compact size and allow to measure 120 times. The test can be performed simply, quickly and easily.