What Causes Etching on Fiberglass Pools?

Acidic Water

• Acidic water is the primary cause of etching issues. Pool water becomes acidic when its pH level sinks below seven; this can occur more easily with soft water or water that has reached a chemical imbalance because of improper chlorine levels. The acidic nature of the water will start to "pull" at the fiberglass coatings, slowly dissolving them.

Gel Coatings

• The gel coatings on the fiberglass pool will be the first to show signs of damage. Sometimes the gel coating will show etching, while the fiberglass resin beneath remains resistant. With acidic water, pool owners need to reapply gel coatings periodically in order to keep protecting their pools. In this case, the coating provides a necessary buffer layer for the fiberglass.

Chalking

• Chalking occurs when the water starts to turn cloudy or when the fiberglass begins to show white streaks. This is actually caused by titanium dioxide that is coming off of the gel coating because of etching. Chalking and etching are actually the same process, and are both caused by acidic water. Chalking may be exacerbated by a gel coating that was not applied correctly.

Other Problems

• Acidic water does not only etch the surface of the fiberglass. That corrosive effect also occurrs inside the pool systems. This means that acidic water can quickly corrode metal parts of the pool, including ladders, heaters and the bolts and gears of pumping mechanisms. A pH increaser can help alter water chemical composition and change the pH level to prevent these long-term problems.