MAG CAL is a Magnesium and Calcium supplement; two essential macro nutrients like NPK although required in smaller quantities so referred to as “secondary nutrients”. Magnesium and calcium supplements are extremely Important for growers in soft water areas, using reverse osmosis filtration or coco based mediums. Calciums primary role in plant growth is to provide strength to cell walls, in the same way we need calcium for our bones. Magnesium is an essential component in chlorophyll and so vital for photosynthesis. Along side these secondary nutrients there is also a blend of trace micro elements for any potential deficiencies.