Which of the following factors contributes to algae growth in swimming pools?

The correct answer is based on the understanding that algae thrive in environments where water chemistry is not properly managed, and sanitation practices are insufficient. Poor water chemistry can mean unbalanced pH levels, inappropriate chlorine levels, or elevated phosphates, which create an ideal environment for algae growth. If sanitation measures are inadequate, such as not maintaining enough disinfectant levels, the pool becomes susceptible to algae outbreaks.

When water chemistry is unstable or inappropriate, it can lead to cloudy water, which not only diminishes visibility but also indicates a lack of proper sanitation, thereby encouraging algae blooms. Ensuring that water is frequently tested and balanced is crucial in preventing algae growth, highlighting the importance of regular maintenance in a swimming pool setting.

In contrast, regular sanitation practices, balanced water chemistry, and frequent pool circulation are all methods employed to prevent algae and generally contribute to a cleaner, healthier swimming environment. These practices help maintain the clarity of the water and the effectiveness of disinfectants, thus minimizing the risk of algae proliferation.