Reef Crystals enriched blend sea salt contains extra levels of calcium, vitamins, and selected trace elements. Developed for use in sophisticated reef aquariums, it was the first enriched sea water formulation available to aquarium hobbyists. The inclusion of important components at concentrations greater than in natural seawater assures extended availability of substances that are assimilated and depleted especially quickly in thriving reef aquariums. A special additive helps to detoxify excess heavy metals, such as copper, that are often found at elevated levels in domestic water supplies. Reef Crystals Salt provides superior dissolvability and is compatible with all marine aquariums. We use only the most sophisticated biological and chemical test methods to develop and refine our formulas, and Reef Crystals Sea Salt is no exception. Every batch is carefully analyzed to guarantee composition, consistency, and uniformity. These items are shipped with actual freight charges that are not calculated in the shopping cart and will be added when we receive your order.