... on deseases like the rotten gill, the red skin, the hemorrhage, the spoiled skin,the rotten tail, the water mildew on ... violation. Addionly it can effectly kill the algae, increase the oxygen,deodorize, the degenerate organic pollutant (ammonia, nitrogen). ... specification: 200g/bags Date of produce:please see the package Production batch number:see certificate Expiry: 2 years chlorine dioxide