This synthetic salt mixture contains all the necessary elements and buffers (except sodium chloride) required to make up to 400 gallons of synthetic seawater. Each phosphate and nitrate free batch is individually tested to generate consistency and high quality. Contains low levels of caustic materials present in other salts that cause “metal plating,” which ruins impellers, pumps and filters. Because sodium chloride is a major component of synthetic sea salt mixtures, it is also responsible for a large amount of the weight of these mixtures. This concentrated mixture contains everything but the sodium chloride, which can be added locally to save money on freight charges. ProLine™ Super Salt Concentrate is packaged in a semi-liquid form and sold in re-sealable buckets. One bucket mixes with 80 pounds of non-iodized, high purity sodium chloride to make 400 gallons (1,514 liters) of saltwater.