Warner Marine Research Concentrated Strontium Supplement Strontium is one of the most controversial elements in the marine and reef aquarium hobby. Expert aquarists worldwide say it may be critical for the formation of a variety of structures, including the skeletons and shells of many corals, clams, algae and other organisms. Warner Marine Research Concentrated Strontium Supplement is an excellent way to add Strontium to the marine and reef aquarium. It is produced entirely from Analytical Reagent Grade (A.C.S.) Strontium Chloride Hexahydrate, the highest quality raw material in the hobby. Inferior products are produced using lower quality raw materials and may add unwanted impurities and toxic heavy metals. Warner Marine Research Concentrated Strontium Supplement is the premier Strontium product available in the hobby. It contains only the highest quality Strontium Chloride Hexahydrate solution in ultra-purified water. We proudly use a 5 stage reverse osmosis/deionization process to ensure the highest quality in the business. Available in 8oz, 16oz, 32oz and one gallon sizes.