However, some wells are exceedingly soft while some public water supplies are exceedingly hard. Why Dissolved Minerals Solidify in Our Plumbing and Appliances Dissolved minerals, primarily bicarbonates of calcium and magnesium, remain within their host complexes under normal conditions. As a result, the dissolved particles, devoid of any nucleation centers for growth and escape from the water, flow evenly within the water having no particular tendency to bind together or lose their solubility. The clumping effect makes it more difficult for the minerals to remain soluble and the crystallized mineral precipitates out of solution and attaches to any available nucleation center, typically your plumbing walls and fixtures. Two types of crystallization occur.
Calcite is an adherent mineral that attaches itself to the surface of the heat exchanger.
Repeated collisions cause the build up of more and more scale on the heat exchange surface. Since mineral scale is an insulator, transfer of heat from the heating element to the water is gradually reduced causing more energy to be consumed to heat the same water. The second type of crystallization occurs when calcium carbonate forms in a lower heat environment away from a heat exchanger. The resulting mineral formation is called aragonite . These deposits remain stable upon heating and can be carried throughout the heating or cooling system causing little or no damage.