Which of the following can result from excessive water hardness in a pool?

Excessive water hardness in a pool leads to scaling on surfaces, which is why this option is correct. When the water contains high levels of dissolved minerals, particularly calcium and magnesium, these minerals can precipitate out of the water and form hard deposits. This scaling can accumulate on various surfaces within the pool, such as tiles, plaster, and even equipment surfaces. Scaling is not only unsightly but can also affect the overall functionality and efficiency of the pool system.

In contrast to this, improved water clarity, corroded pool equipment, and simplified maintenance procedures would not typically result from hard water. Increased hardness tends to cloud water clarity rather than improve it; in fact, it can create a breeding ground for algae and other microorganisms. While some minerals can be corrosive under certain conditions, excessive hardness typically leads to scaling rather than corrosion. Additionally, maintenance procedures often become more complicated due to the need to manage and remove scaling, making it harder—not simpler—to maintain a balanced pool environment.