AquaPro ARO Series 7 Stages With UV-Ultraviolet 200 Gallon Per Day Reverse Osmosis (RO) drinking water Purification systems include mechanical filtration to remove particles, carbon absorption and absorption to remove chloring, taste, odor and chemical contaminants, as well as membrane separation down to 0.0001 microns. RO membranes remove dissolved solids at the ionic level. No other purification system can provide better removal.