Instant Ocean® Reef Crystals Aquarium Reef Salt. Create a perfectly balanced and nutrient-rich environment for your saltwater coral reef with Instant Ocean® Reef Crystals Aquarium Reef Salt, designed to mix into enough solution for 160 US Gallons. This premium salt blend is scientifically formulated with extra calcium, magnesium, and other trace elements to encourage the robust growth of corals, clams, and other invertebrates. Its unique formulation ensures that vital elements are replaced during routine water changes, promoting stable water chemistry and optimal coral health without leaving any residue. Instructions: Mix the required amount of salt with RO or DI water until the desired specific gravity (typically 1.024-1.026) is reached, and then perform your water change to maintain a thriving, crystal-clear reef tank.