What is the primary reason the pH of a pool should stay less than 8?

The primary reason for maintaining the pH of a pool below 8 is that a higher pH level can decrease the efficacy of chlorine as a disinfectant. Chlorine exists in different forms depending on the pH, and the form known as hypochlorous acid is the most effective in killing germs and pathogens. As the pH increases beyond 7.5, the presence of hypochlorous acid diminishes, leading to a decrease in the overall disinfection potential of the chlorine present in the water. This can result in inadequate sanitation and could potentially lead to waterborne illnesses. Keeping the pH below 8 ensures optimal chlorine activity, thus maintaining a safe and clean swimming environment.