Aquarium Systems Reef Crystals, an enriched sea salt mixture, contains a supplementary dose of calcium, vitamins and selected trace elements. Developed for use in refined reef tanks, it was the first enriched sea salt formulation available to amateurs. The introduction of important compounds at higher concentrations than in natural seawater ensures longer availability of the substances assimilated and quickly used up in a flourishing reef aquarium. A special additive helps to eliminate surplus heavy metals, like copper, which are often found at excessive levels in flourishing reef aquariums. Each batch is analysed to guarantee ist composition and uniformity.Aquarium Systems Reef Crystals Element levels at different salinities:1020: Calcium: 415 mg/l, Magnesium: 1081 mg/l, CH: 8.4d1022: CalCium: 440 mg/l, Magnesium: 1140 mg/l, CH: 9.1d1024: CalCium: 450 mg/l, Magnesium: 1275 mg/l, CH: 9.1d4 kg for 110 litres10 kg for 275 litres15 kg bag for 410 litres20 kg in 10x 2 kg packages for 55