Which method is used to decrease the pH level in pool water?

To decrease the pH level in pool water, the appropriate method is to add acid. Acids, such as muriatic acid (hydrochloric acid) or sodium bisulfate, are effective at lowering pH levels because they increase the concentration of hydrogen ions in the water, which consequently reduces the pH.

Maintaining proper pH levels is crucial for the effectiveness of disinfectants, such as chlorine, and to prevent issues like scale formation or corrosion of pool equipment. Ideally, the pH level in pool water should be maintained between 7.2 and 7.8 for optimal sanitization and comfort for swimmers.

In contrast, adding a base would increase the pH level, and adding salt wouldn’t impact the pH significantly. Enzymes serve a different purpose, primarily helping to break down organic contaminants, but they do not alter pH levels.