Water Softeners work to convert hard water into soft water. Hard water has minerals like calcium and magnesium which are positively charged ions. The presence of positive charged ions is what causes calcium and magnesium to dissolve less easily in water. As a result of the high concentration of minerals, water tastes "salty" even though there is no sodium present. Water Softeners not only work to remove excessive calcium and magnesium but also to remove iron, lead, radium, copper, and sediment. The main principal that softeners operate on is the ion exchange. Water softeners all have a resin tank which contains the ion exchange brine tank and the control head which is the mechanism that determines when the regeneration process is to take place. In the resin tank are resin beads which contain sites that hold sodium or potassium ions. The positively charged hard water ions are attracted to the beads and exchange themselves with the sodium or potassium ions. The process continues until there are no more sites for the exchange to take place and the resin is considered exhausted and must be "regenerated". During this process, the sodium or potassium brine solution is rinsed throught the resin leaving the calcium/magnesium and other hard water minerals to be bumped off and discarded down the drain. Many concerned about salt intake in their diet will worry if the sodium exchange in the water softening process will have an ill effect on their health. The FDA definition for sodium in drinking water is: sodium free=up to 28 mg,very low sodium=28 to 197 mg and low sodium=197-789 mg. The amount of sodium in water exchanged by a water softener is considered a trace amount and will not be harmful for anyone wishing to limit their sodium intake. 10 grains of hard water ions per gallon will be exchanged to 78 mgl sodium, 15 grains exchanged for 119 mgl sodium and 20 grains for 158 mgl sodium. Potassium chloride salt subsitute is also widely available but a bit more costly than sodium. You may have heard the term grain capacity when considering a water softener and wonder exactly what it means and how to calculate it. Grain capacity = how much hardness the softener will remove before it requires regeneration. 1.0 cubit foot of resin = 30,000 grain capacity
1.5 cubit foot of resin = 45,000 grain capacity
2.0 cubit foot of resin = 60,000 grain capacity Depending on your family's daily water use and how hard the water is will determine the grain capacity required. It is suggested to purchase a water softener with the grain capacity to allow for regeneration no less than 3 days apart. |
