FloraFlex Cal+Mag+Iron is a Calcium, Magnesium, & Iron supplement designed to complement the FloraFlex 2-part base nutrient formulas. Some plants may require more of these elements under rapid growth and/or developmental phaes. The product corrects common deficiencies when using reverse osmosis water, as well as plants grown in coco coir, rockwool and/or any hydroponic growing media. Directions for use: Reservoir Feeding: Add 2-4 mL per gallon of water during all stages or as needed. Foliar Feeding: Add 15 mL per gallon of water. Shake well before use Adjust pH to proper levels after mixing all fertilizers and additives Recommended for hydroponic use, but is compatible with soil