odors - Are self-descriptive. Odors are sometimes transmitted to the sample by the shipping container when it is not a standard Culligan sample bottle.

operating pressure- The range of pressure, usually expressed in pounds per square inch, over which a water conditioning device or water system is designed to function.

organic matter- Substances of or derived from plant or animal matter. Organic matter is characterized by its carbon-hydrogen structure.

osmosis - A process of diffusion of a solvent such as water through a semipermeable membranae which will transmit the solvent but impede most dissolved substances. The normal flow of solvent is from the dilute solution to the concentrated solution in an attempt to bring the solutions on both sides of the membranae to equilibrium. (See equilibrium, reverse osmosis.)

oxidation - A chemical process in which electrons are removed from an atom, ion, or compound; causing the substance's valence to increase. The addition of oxygen is a specific form of oxidation; combustion is an extremely rapid form of oxidation, while the rusting of iron is a slow form. Whenever oxidation occurs, an offsetting reduction reaction must occur. (See reduction.)

ozone - An unstable form of oxygen (O₃), which can be generated by an electrical discharge through air or regular oxygen. It is a strong oxidizing agent and has been used in water conditioning as a disinfectant.