PondCare Pond Salt provides essential electrolytes fish need to survive with an all-natural salt, made from evaporated sea water. Improves gill function, protects against nitrite toxicity & reduces stress by helping to maintain a natural balance of electrolytes in the body fluids of pond fish. Pond Salt can safely be used with all PondCare water conditioners, filtration materials, medications & fish foods. Pond Salt contains no artificial additives, sugar, or color like table salt. It is made from evaporated sea water, which contains the following beneficial electrolytes needed by freshwater fish: calcium chloride, magnesium chloride, magnesium sulfate, potassium chloride, and sodium chloride. Treats up to 550 gallons. Shipping weight: 5 lbs.