Sera Test-Set Ca for the exact and reliable determination of the calcium content in sea water. In reef aquariums, calcium is required by ornamental algae, corals, and other invertebrates. For healthy coral growth, the calcium level in marine aquariums should be about 420 mg/l (ppm). The sera test Ca is very exact and shows the calcium content in steps of 20 mg/l. The test is sufficeint for approx. 7500 mg calcium. Sera Test Ca Calzium+ monitor the calcium level in aquariums according to scientific standards+ precise measurement in 20 mg/l (ppm) steps+ allows precise adjustment of the Ca level, for optimal coral growth+ complete kit with vial, syringe, measuring spoon, and evaluation chart for precise water analysis+ with a readily understandable video tutorial for easy use