Why should demineralized water be used for panel cleaning instead of tap water?
The calcium, magnesium and silica in tap water leave limescale marks when they evaporate on the hot panel surface. These marks cause micro-shading and can permanently erode the anti-reflective coating on the glass. At the very least the final rinse should be done with demineralized, deionized or reverse osmosis water.
The problem is not the water itself but the dissolved minerals in it. The panel surface is hot under the sun; the water evaporates quickly and the minerals stay where they are.
- Limescale mark: calcium and magnesium residue leaves a white trace on the glass, scattering light and creating micro-shading.
- Silica: forms a film that hardens over time and does not come off with normal cleaning.
- Coating wear: repeated mineral residue and the aggressive cleaning needed to scrape it off permanently damage the glass's anti-reflective coating. That loss does not come back.
Practical application: even if the main body of the wash is done with normal water, the final rinse must be done with demineralized or deionized water. A reverse osmosis output is also suitable. Pure water also reduces the need for detergent, because it leaves no residue.
In systems that work by applying water to the panel surface, water quality is as decisive as the brush used. To check whether your site water is suitable, consult our technical team.