Hydro-Logic Evolution RO1000 MembraneThis HydroLogic Membrane Element reduces 94%+ of total dissolved solids. For all membranes, RO output depends on the source water temperature. At 77 degrees, the system should produce 100% of the rated output. As the temperature drops or increases, so does the output. Replace membranes when product water decreases and or ppm increase. Replace when product water decreases and or ppms increase. Let water run for one hour before use. The Evolution RO