FritzPro Magnesium Sulfate is a concentrated magnesium salt designed to increase magnesium levels in reef systems. Magnesium is the third most abundant ion in seawater, and is integral for biological processes and coral health. A healthy level is maintained at 1250-1350 ppm, and is depleted via calcification. Low levels can lead to low pH and difficulty in maintaining calcium and alkalinity levels. FritzPro can be used to aid calcium stabilization, and can be mixed with FritzPro Magnesium Chloride to match natural seawater ratios. Usage: Dissolve 3.5 g/10 gallons in RO/DI water and dose slowly. Re-test and dose as needed, up to 100 ppm per 24 hours. CAUTION: May become hot when mixed with water. Store in a cool, dry place.