Key Features:*Eliminate toxins and heavy metals substances in aquarium.*Provided essential vitamins and minerals for optimum growth of fish.*Strengthen fish immunity system and able to prevent harmful infectious diseases.*Prevent Eutrophication in the aquarium and improves water quality.*100% natural organic substances and improves skin and color of fishes.*Can be use for marine and freshwater aquariums. Purify Water Quality (净化水质) Prevention Infectious (预防传染病) Conversion Digestive (改善消化系统) Natural Supplements (补充天然微量元素) How to Use: 2ft x 1.5ft x 1.5ft = (2.5g) 3ft x 1.5ft x 1.5ft = (5g) 4ft / 5ft x 2ft x 2ft = (7.5g) 6ft x 2ft x 2ft =(10g) 7ft / 8ft x 2ft x 2ft =(12.5g)