Warner Marine Research Concentrated Calcium Supplement is the premier Calcium product available today. It is produced entirely from Analytical Reagent Grade (A.C.S.) Calcium Chloride Dihydrate, the highest quality raw material in the hobby. Warner Marine Research is the only manufacturer to use these fine quality raw materials. It is also highly concentrated, containing over 115,000ppm Calcium making it highly cost effective compared to lower quality competing products. Most importantly Warner Marine Research Concentrated Calcium is highly effective at adding high quality bio-available Calcium without the unneccesary impurities found in the competitors products.