HydroHort's Cal-N-Mag formulation contains calcium, magnesium, and iron. Our Cal Mag Supplement improves stalk and leaf growth and prevents common deficiencies Fully compatible with all growth mediums and can even be applied as a foliar spray for rapid uptake. Hydrohort's calcium and magnesium supplement are specialized nutrients designed to compensate for deficiencies in most nutrient and fertilizer schedules.  Calcium and Magnesium (often referred to as Cal-Mag) is almost always needed when using pure, distilled, or reverse osmosis water. Calcium and Magnesium are the most abundant minerals in tap water however much of it is not chelated enough to be absorbed by plants Calcium, an essential part of the plant’s cell wall structure, improves the absorption of other nutrients by the roots. It helps to activates a number of plant growth-regulating enzyme systems. Calcium also helps convert nitrate-nitrogen into forms needed for protein formation; and contributes to improved disease resistance. Magnesium also helps to activate specific enzyme systems. Enzymes are complex substances that build, modify or break down compounds as part of a plant’s normal metabolism. Hydrohort's Cal-N-Mag Supplement is a highly fortified calcium, magnesium and iron plant supplement formulated to correct common deficiencies. Supplementing your preferred nutrient program with Hydrohort's Cal-N-Mag Supplement is strongly recommended when using reverse osmosis water and when growing in coco coir based medias to compensate for natural calcium draw. Cal-Mag Supplement can also be applied as a foliar spray to further enhance growth.