Pro-Cal Supplement Pro-Cal is a highly beneficial calcium, magnesium and iron plant nutrient supplement. This recommended application rate normally is sufficient to make up for any deficiencies in most soil or hydroponic formulas. Pro-Cal is more concentrated than competitive products and helps increase overall density in your plants. It remedies yellowing plants and helps resist disease. *Not for Sale or Use in the state of California C.A.P. Custom automated products pro-cal 1 liter hfpc1l
