E.S.V. Aquarium Products is an aquarium supply company out of New York that specializes in aquarium additives and supplements. Among their well-known and reliable products are the B-Ionic series of Calcium Buffer System (a 2 Part liquid Alkalinity and Calcium product) and their liquid Magnesium. Additionally E.S.V. carries powdered Calcium Chloride and Calcium Hydroxide (Kalkwasser), 20% solution of Strontium Chloride and 1% solution of Potassium Chloride to help maintain proper water balance as well as Granular Activated Carbon for filtering aquarium water.