What causes scale to form on surfaces in a swimming pool?

Scale formation in a swimming pool is primarily attributed to high levels of calcium hardness, pH, or total alkalinity. When the concentration of calcium and other minerals in the water increases, especially in combination with elevated pH levels, it can lead to the precipitation of calcium carbonate. This process occurs when the water becomes supersaturated with these minerals, causing them to deposit on pool surfaces as scale.

Maintaining proper chemical balance is crucial in preventing scale formation. If the pH is too high or if total alkalinity is not maintained within recommended levels, it can exacerbate the issue. Regular testing and balancing of water chemistry are essential in managing calcium hardness and ensuring the water remains stable, thereby preventing scale buildup that can damage pool surfaces and equipment.