Glossary & Terminology

Absolute filter rating
Refers to the smallest particle size that a filter will trap 100 percent. For example, a 5-micron absolute filter will trap all particles 5 microns and larger. See nominal filter rating.
The process by which filters hold or trap particles and chemicals by absorbing them. Picture a sponge.

Activated carbon
       Carbon that has been specially treated to enhance its ability to trap certain chemicals.

The process by which carbon filters trap chemicals by holding them on the surface. Picture a magnet holding something on the surface.
The process of exposing water to large amounts of oxygen in order to remove certain kinds of chemicals.
Aggressive water
Water that, because of its purity, aggressively reacts (chemically) with materials.
A negatively charged ion. See also Cation.

         A naturally occurring underground reservoir.

Backwashing, back flushing
     Reversing the flow of water through a filter in order to cleanse it of accumulated particulate matter.

CA membrane
      Cellulose acetate membrane. A type of membrane used in reverse osmosis.