ASM533 Reef Plus is a full spectrum reef supplement containing trace elements; vitamins; and amino acids demonstrated to have a positive impact on the growth of corals and other desirable reef creatures. Reef Plus is formulated to provide nutrients available from natural tropical reef waters. Contains vitamin B12; vitamin C; thiamine; inositol; choline; iodide; and other essential constituents at pH 8.3. Reef Plus is nitrate/phosphate free. 500 mL treats 2000 gallons.