Strontium is found in the bones of fish and more importantly in aragonite the mineral secreted by reefbuilding marine invertebrates such as corals clams tube worms and their respective allies. Overall strontium accounts for between 0. 75 1. 00% of aragonite’s total mass and findings suggest that strontium itself induces inorganic precipitation of other ions creating a biogenic aragonite. Rapid growth rates of corals and other reefbuilding invertebrates witnessed when strontium is maintained at the natural seawater concentration of approximately 8 ppm suggest this element’s importance in the marine environment. The rate at which strontium is extracted from the water is determined by the stocking density of reefbuilding livestock type of lighting and other biological physical and chemical conditions; therefore each aquarium will have different requirements for the rate of strontium supplementation. Once the rate of strontium uptake in the aquarium has been determined the proper dosing rate of this product can be easily calculated. It is recommended that a quality salt mix with the proper (not augmented) alkalinity and concentrations of major minor and trace elements be used to establish natural seawater parameters in the reef aquarium providing a stable ionic foundation on which to build. The basis of healthy rapidlygrowing reefbuilding invertebrates is simply providing proper physical and chemical conditions. Maintaining calcium magnesium and strontium at natural seawater concentrations and alkalinity between 7 12 dKH is the first step towards achieving this goal. All Brightwell Aquatics liquid water care supplements are made with purified water and high purity materials. We develop formulae for aquaria based on empirical data using observation and measurement rather than theory.