Blagdon Guardian Pond Tonic Salt, for Fish Health, Water Quality, General Tonic, pH Buffer, 9.08kg, treats 9,092 litresReduces fish stress, promotes fish health; contains essential physiological salts that fish need to thrive Protects fish against disease and helps fish recover from stress and illness following disease treatments Highly effective and easy to use, can be added directly to your pond as a general tonic, pH buffer, anti stress agent, or as a supportive measure Follow the easy, step by step instructions on the back of pack to add the correct amount of salt