Cal Mag Plus Concentrate Cal Mag Plus Solution"Greenway Biotech Brand" 2.5 Pounds = 1 Gallon 2.5 Pounds of Greenway Biotech Cal Mag Plus Concentrate Makes 1 Gallon Great as Calcium, Magnesium, and Iron EDTA Supplements for Hydroponics This Bag (2.5 Pounds) Makes 1 Gallon of Cal Mag Plus Solution Total Nitrogen (N): 2.0%, 2.0% Nitrate Nitrogen Calcium (Ca): 3.2% Magnesium (Mg): 1.2%, 1.2% Water Soluble Magnesium (Mg) Iron (Fe): 0.1%, 0.1% Chelated Iron (Fe)