2-0-0. Corrects common deficiencies. Cal Mag Plus is a highly fortified calcium, magnesium and iron plant nutrient formulated to correct common deficiencies. Adding Cal Mag Plus to your plant feeding regimen is recommended when using reverse osmosis water, and when growing in coco coir based medias to compensate for natural calcium draw. Cal Mag Plus can also be applied as a foliar spray to further enhance growth.