Jack's Nutrients Epsom Salt 25 lbsJack's Professional Magnesium Sulfate is part of the BOOST line of products and is an essential item for the Jack's 3 2 1 program. This nutrient supplement is backed by scientific research and quality testing. The Mg + S (magnesium and sulfur) in Jack's Nutrients Epsom Salts undergoes extensive quality testing to ensure the lowest possible levels of heavy metals. You can have confidence that when you add a boost of Mg + S, you are getting pure