Spectra recommends flushing your watermaker after every use. Why? Seawater contains two things that can shorten the life of any RO membrane; minerals and living organisms. If seawater is allowed to remain in contact with the membrane, minerals will begin to adhere to the surface; a fresh water flush will actually dissolve many minerals and stops this from happening. Seawater is also full of microscopic life and as the oxygen is consumed when the system stops, these organisms begin to die and decay. This decay causes biofouling which smells bad and will also lead to low-oxygen corrosion that will attack the stainless steel components critical to the function of any watermaker. Fresh water flushing virtually eliminates all these problems.