Some brewers prepare their brewing water using Magnesium Sulphate to increase the sulphate and magnesium ions instead of modifying the water with calcium sulphate aka gypsum. The amount of magnesium sulphate used typically is less than calcium sulphate, about 50%. One gram of magnesium sulphate in 3.785 liters changes the salt levels by 103 ppm of sulphate ions 26 ppm of magnesium ions and adds 108 ppm to the hardness based on the literature.