Continuum Aquatics Halcyon Marine Reef Salt Precision formulated and balanced blend that replicates natural seawater for all marine and reef aquaria, 14.7 LBS, Makes 50 Gallons Manufactured in small batches under strict quality control safeguards Does not utilize any natural seawater desalinization residue or wastes but is entirely manufactured from reagent grade, pharmaceutical grade, and tested and assayed ingredients Halcyon has been developed through 20 years of testing and experience in manufacturing salt mixes