As well as preventing limescale buildup, Wave's Limescale Eliminator technology can remove existing scale. To understand how this occurs we need to look at the chemistry of the crystallization process in a bit more detail.
When the dissolved calcium and bicarbonate ions crystallize, they form calcium carbonate (limescale), carbon dioxide and water. This process, however, can go both ways, as water and carbon dioxide together can dissolve limescale.
Figure 7: The reaction by which calcium and bicarbonate ions form calcium carbonate,
carbon dioxide, and water.
Figure 8 shows what happens when the Limescale Eliminator's technology is applied to a system with existing scale. 1) The Limescale Eliminator signal forms clusters in the water. 2) When the water is heated, it becomes supersaturated and the clusters form crystals of calcium carbonate, releasing carbon dioxide. 3) The carbon dioxide can now dissolve the existing scale in the system.
Figure 8: Dissolving existing scale with the Limescale Eliminator technology.
In order to dissolve the existing scale, the Limescale Eliminator requires carbon dioxide in the water. This, in turn, requires that dissolved ions of calcium and bicarbonate are converted into crystals of calcium carbonate plus carbon dioxide. In order to dissolve existing scale, HydroCare’s technology needs the incoming water to contain calcium ions. If these ions have been removed chemically through water softening the Limescale Eliminator cannot dissolve existing scale. In order to dissolve existing scale, Wave's technology requires a hard water feed.