Culligan Mark 100 Owner's Manual page 6

How Your Water Conditioner Works
Why Water Gets Hard And How It's Softened
All of the fresh water in the world originally falls as rain, snow, or sleet. Surface water is drawn upward by the sun, forming clouds. Then,
nearly pure and soft as it starts to fall, it begins to collect impurities as it passes through smog and dust-laden atmosphere. And as it seeps
through soil and rocks it gathers hardness, rust, acid, unpleasant tastes and odors.
Water hardness is caused primarily by limestone dissolved from the earth by rainwater. Because of this, in earlier times people who wanted
soft water collected rainwater from roofs in rain barrels and cisterns before it picked up hardness from the earth.
Some localities have corrosive water. A softener cannot correct this problem and so its printed warranty disclaims liability for corrosion of
plumbing lines, fixtures or appliances. If you suspect corrosion, your Culligan Man has equipment to control the problem.
Iron is a common water problem. The chemical/physical nature of iron found in natural water supplies is exhibited in four general types:
1. Dissolved Iron - Also called ferrous or "clear water" iron. This type of iron can be removed from the water by the same ion exchange
principle that removes the hardness elements, calcium and magnesium. Dissolved iron is soluble in water and is detected by taking a
sample of the water to be treated in a clear glass. The water in the glass is initially clear, but on standing exposed to the air, it may
gradually turn cloudy or colored as it oxidizes.
2. Particulate Iron - Also called ferric or colloidal iron. This type of iron is an undissolved particle of iron. A softener will remove larger
particles, but they may not be washed out in regeneration effectively and will eventually foul the ion exchange resin. A filtering
treatment will be required to remove this type of iron.
3. Organic Bound Iron - This type of iron is strongly attached to an organic compound in the water. The ion exchange process alone
cannot break this attachment and the softener will not remove this type of iron.
4. Bacterial Iron - This type of iron is protected inside a bacteria cell. Like the organic bound iron, it is not removed by a water softener.
When using a softener to remove both hardness and dissolved iron it is important that it regenerates more frequently than ordinarily would
be calculated for hardness removal alone. Although many factors and formulas have been used to determine this frequency, it is recommended
that the softener be regenerated when it has reached 50 - 75% of the calculated hardness alone capacity. This will minimize the potential for
bed fouling.
If you are operating a water softener on clear water iron, regular resin bed cleaning is needed to keep the be from coating with iron. Even
when operating a softener on water with less than the maximum of dissolved iron, regular cleanings should be performed. Clean every six
months or more often if iron appears in your conditioned water supply. Use resin bed cleaning compounds carefully following the
directions on the container.
CAUTION: Do not use where the water is microbiologically unsafe or with water of unknown quality
without adequate disinfection before or after the unit.
4 CULLIGAN MARK 100 WATER SOFTENER OWNER'S GUIDE
®