RO Osmosis Membrane - An ultra-fine porosity (single pore size 0.0001 micron) filter operating on the reverse osmosis principle. When pure water and saline are separated by a semiconducting membrane that passes only water molecules, due to the pressure (concentration) difference on both sides of the membrane, the water molecules pass to the saline side. This process takes until the salt concentration on both sides equalizes. This process is called direct osmosis. Treatment of highly mineralized water with a reverse osmosis membrane creates a pressure in excess of osmotic and forces water molecules to flow through the membrane in the opposite direction to direct osmosis, that is, from highly mineralized water to the pure water section. Membrane holes are much smaller than viruses and bacteria, so they are removed by filtration. Heavy metals, dissolved substances, salts are also removed. The membrane finally removes nitrites, nitrates, heavy metals, radioactive and concorogenic elements. The membrane transmits only water because its porosity corresponds to the size of the water molecule.