Fritz ProAquatics Reef Pro Mix (RPM) is manufactured using only the highest quality raw materials. Formulated by researchers and marine scientists, RPM contains all of the necessary major and minor elements of natural sea water that are utilized by living marine and reef animals. Correct pH and buffering capacity, essential minerals and trace elements have been added in precise ratios to ensure a correctly blended mix for the health and longevity of your livestock. RPM is manufactured in our own facility in small batches to ensure complete quality control, rather than outsourced to generic chemical blenders with uncertain quality. Our salt blending equipment is devoted solely to the production of aquatic products, preventing contamination issues. Fritz's unique production process promotes a uniform particle size minimizing stratification of the salts. Each batch is assigned a lot number and tested by in-house quality control to ensure its chemical quality and purity before it is shipped. RPM is used by public aquariums, zoos, research institutions, destination retail locations, adventure parks and hobbyists worldwide. Parameters: Salinity 35 ppt (1.0264 sg) Calcium 400-450 ppm Magnesium 1350-1450 ppm Alkalinity 8.0 - 9.0 dKH Strontium 9 ppm Potassium 400 ppm. RPM parameters reflect Fritz Aquatics' QC pass ranges, the median is targeted. Be aware source water can greatly affect parameters especially alkalinity. QC is conducted using RO/DI at a neutral pH and a TDS of 0.