Balanced salts are a combination of inorganic salts and normally a carbohydrate. They act as buffer to protect cells from sharp fluctuactions in ph while maintaining the proper osmotic pressure across the cell membrane.In a complete medium, balanced salts are essential to the growth and maintenance of cells in culture. Alone balanced salts are generally used as a cell rinsing fluid and for short-term maintenance while cells are manipulated outside a complete growth environment. We recommend using the entire contents of each package immediately after opening. We do not recommend preparing concentrates solution of media or salts from a powdered base due to the potential formation of insoluble salt complexes and precipitates.