Water softeners have been around for many years and are still the best solution available to get rid of limescale in water. The process that water softeners use to remove lime from water is called ion exchange. Simply put ion exchange is when hardness ions (lime) in the water are replaced by sodium or potassium ions (salt). The resin beads are all loaded with sodium ions and when the water passes over the resin the sodium trades places with the calcium and magnesium in the water. The calcium and magnesium then stick to the resin. This is also why the water has a higher sodium content afterward and can taste very different from before. The sodium however has no adverse effects when using the water.
