Be confident in your purchase we're an Authorized ATI Dealer. How cool is that?!?!? Magnesium aids in the regulation of aquarium calcium and carbonates and the formation of skeletal structures in invertebrates. ATI?s line of water treatment products is a comprehensive care system for your aquarium. By using ATI Essentials you can work smarter?not harder?to supply all the essential elements your tank needs in one easy-to-use system.