Strontium Supplement for all Marine Fish & Reef Aquaria Overview High-purity powdered strontium. Incorporated by corals, clams, and other reef-building invertebrates into aragonite, the mineral that is secreted as skeletal material. Stronger and more economical than liquid strontium solutions; created for hobbyists maintaining multiple reef aquaria. Formulated by a marine scientist. It is recommended that the strontium concentration in the aquarium be determined by using an accurate test kit prior to supplementing. Do not add this product directly to an aquarium containing live animals without first diluting in water as directed.