Emerald Harvest Cal-Mag (2.5 US gal / 9.46 L), Case (2 Qty), is a professional-grade calcium and magnesium supplement designed to prevent nutrient deficiencies and promote vigorous plant growth. This case includes two 2.5-gallon containers, making it ideal for medium to large-scale growers who require a steady supply of essential nutrients.Calcium and magnesium play a critical role in... https://www.hydroponicstown.com/cal-mag-2-5-us-gal-9-46-l