Tropic Marin Bio-Strontium is biologically Ideal Strontium Supplement for Reef Aquariums. A sufficient supply of strontium and carbon dioxide is as essential for the growth and well-being of reef-building corals as calcium. Both elements are supplied to the corals with the help of the zooxanthellae (algae) that live symbiotically within them. Bio-Strontium creates a natural environment in the aquarium and delivers strontium and carbon dioxide in a natural, biologically-available ionically balanced form. Key Benefits: - Contains strontium carbonate for corals and carbon dioxide for zooxanthellae. - Measured amount of strontium in a truly ionically balanced formula. - Contains all 70 trace elements found in natural sea water. - Only natural substances are formed when dissolved: no chelates, no phosphates, no nitrates. Dosage: 1 level measuring spoon increases the strontium level of 10 US Gal. / 8 Imp.Gal. / 37 l by about 2 ppm (2 mg/l). The natural concentration of seawater is 8 ppm (8 mg/l). In a reef aquarium the concentration of strontium decreases quickly through biological processes, precipitation and by the use in calcareous animals. A basic dosage of 1 level measuring spoon per 50 US Gal. / 42 Imp.Gal. / 190 l every two weeks is recommended. In an aquarium with a high population, the dosage can be as much as 1 level measuring spoon per 50 US Gal. / 42 Imp.Gal. / 190 l each week. High strontium concentrations in the aquarium may damage corals. Always be sure to monitor the strontium concentration with a Strontium Test.