Kent Marine Liquid Calcium 8 oz.,Concentrated Liquid Calcium provides bio-available calcium for lush growth of purple, pink and green calcareous algae, snails, hard tube worms and clams. Corals will open more and stay attached to their skeletons better with regular use. Phosphate and nitrate free! Contains no gluconates, EDTA, or other organic to raise DOC levels, as many competing products do. Concentrated Liquid Calcium alone can provide all the calcium your reef will need, but for maximum results use Kent Kalkwasser Mix first, then raise calcium level with this product. Strontium addition via use of Kent Marine Strontium and Molybdenum Supplement is absolutely necessary. Use of Coral-Vite and Essential Elements are beneficial as well.Directions:Add ï¿½ to 1 teaspoon (1/4 to 1 capful or 1.25 to 5 ml) per 50 gallons (190 to l) of tank capacity each day, based on animal load. Since animals use calcium, and gallons do not, regular testing of calcium level by a good calcium test kit is advised. Adjust amount of addition of the product to achieve a calcium level of about 400 mg/l. A higher level may result in rapid calcium compound precipitation and deposits which can possibly be destructive to pumps and other sensitive system equipment. It is recommended that you regularly check impellers and other delicate equipment for calcium deposits if you run higher (above 400 mg/l) system calcium levels! For best results adjust system KH to 8 to 10 dKH with Superbuffer-dKH or Marine Aquarium pH Buffer.