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Symptoms of Hard Water
Hard water is fine for many uses around a home. To water a garden, wash down a driveway and general outdoor lawn care, most water, as it comes from a well or from a municipal treatment plant, works fine. But for indoor use such as bathing, showers, doing dishes and washing clothes, shaving, washing china and flatware, and dozens of other uses, hard water is not as efficient or beneficial as "soft water."
For instance, hard water: |
- Requires more soap and cleaning products
- Leaves a "soap scum" that's difficult to remove, and 'bathtub ring'
- Leaves unsightly spots on dishes, glassware and flatware
- Increases hardness scale in the water heater, plugs plumbing, and increases electric or gas bills,
- Shortens life of appliances
- Leaves deposits on skin and hair
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Background on Hard Water
Hard water is probably the most common water problem found in homes in the United States. The most common hardness-causing minerals are calcium and magnesium that are dissolved in a water supply. According to the Water Quality Association (WQA), hard water is water that contains dissolved hardness minerals above 1 GPG (grains per gallon). Relative levels of hardness have been established as follows: |
- Soft Water - less than 1 gpg
- Slightly hard - 1 to 3.5 gpg
- Moderately hard - 3.5 to 7 gpg
- Hard - 7 to 10.5 gpg
- Very Hard - 10.5 and higher gpg
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Use of both grains per gallon and milligrams per liter is a practice followed primarily for convenience in reporting concentrations of minerals, some of which are abundant in water and some of which are found only in trace quantities. One grain per gallon equals 17.1 milligrams per liter or parts per million.
By definition, “Total Hardness” is the sum of the concentrations of calcium and magnesium, both expressed in “calcium carbonate equivalents”. Some water analyses show only the calcium and magnesium values, and these usually are expressed as the separate elements. These values cannot be added together to determine Total Hardness; they must first be converted to calcium carbonate equivalents. This is like the adage, “You can’t add apples and oranges; you have to convert both to grapes”. To convert the calcium concentration from calcium to calcium carbonate equivalents, multiply by 2.5; to convert calcium and magnesium to calcium carbonate equivalents, multiply by 4.12.
Example:
A water analysis shows a calcium level of 30 mg/L as calcium, and a magnesium level of 20 mg/L as magnesium.
30 mg/L as calcium x 2.5 = 75 mg/L of calcium as calcium carbonate
20 mg/L of magnesium x 4.12 = 82.4 mg/L of magnesium as calcium carbonate
The Total Hardness is 75 + 82.4, or 157.4 mg/L. Dividing by 17.1 to convert to grains per gallon, the Total Hardness is 9.2 gpg. |
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Treatment Options
If water tests over 1 GPG hard, consider softening with a water conditioner. There are only two practical ways to treat hard water: Chemical treatment or mechanical treatment. In chemical treatment, various detergents and other substances are used to "cover up" or hide some of the negative effects of hard water. Using mechanical treatment, hardness minerals are physically removed from the water.
The most common mechanical way to soften water is through the use of an ion exchange water softener. This device uses an ion exchange process to replace hardness minerals in the water with some other substance. The vast majority of water softening equipment today uses the exchange of hardness minerals for sodium. (To see the water softener options that Culligan offers, click here or talk to your Culligan Man®.)
The process consists of flowing the hard water over a bed of plastic resin beads. On each bead, slight electric charges hold sodium ions on the surface of the bead. However, these beads also have the ability to attract and hold hardness minerals. As hard water flows through the water softener, it passes around the plastic beads. The hardness minerals (ions) in the water have a greater attraction to the bead than the sodium on the bead. Therefore, they attach themselves to the bead, and in the process they displace the sodium ions. Thus the name ion exchange. Hardness ions are exchanged for sodium ions.
Eventually, the plastic resin bead will be covered with hardness ions. When this occurs, the removal of hardness will be diminished. The water softener in this condition is known as having "exhausted" resin. In order to remove additional hardness from the water, a means must be found to clean the resin beads of accumulated hardness ions. This is accomplished by a process called regeneration. A brine solution is introduced into the resin tank. The extreme concentration of sodium ions in the brine solution scrub the hardness ions from the resin beads. The resin material is then flushed with clean water and the excess brine and accumulated hardness is flushed away, leaving the beads ready to remove additional hardness. |
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Concentration of Hardness as Calcium
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 | | Credit: U.S. Geological Survey | |
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