In order to lower the pH value of water in a pool, add

In order to lower the pH value of water in a pool, add

• A. Sodium hypochlorite
• B. Sodium bicarbonate
• C. Calcium carbonate
• D. Muriatic acid

Answer: (D)

Lowering pH in pool water is done by adding an acid. The pH value shows how acidic the water is, and acids provide hydrogen ions that push the water toward acidity, decreasing the pH. Muriatic acid (hydrochloric acid) is commonly used for this purpose because it is a strong acid that effectively lowers pH. Other options either raise pH or have little effect on it: sodium hypochlorite is basic and tends to raise pH, sodium bicarbonate mainly increases total alkalinity (and can raise pH only slightly), and calcium carbonate raises pH and alkalinity slowly but not to lower pH. So to decrease pH, add muriatic acid. Handle acids safely—add acid to water with the pump running and never add water to acid.

Lowering pH in pool water is done by adding an acid. The pH value shows how acidic the water is, and acids provide hydrogen ions that push the water toward acidity, decreasing the pH. Muriatic acid (hydrochloric acid) is commonly used for this purpose because it is a strong acid that effectively lowers pH. Other options either raise pH or have little effect on it: sodium hypochlorite is basic and tends to raise pH, sodium bicarbonate mainly increases total alkalinity (and can raise pH only slightly), and calcium carbonate raises pH and alkalinity slowly but not to lower pH. So to decrease pH, add muriatic acid. Handle acids safely—add acid to water with the pump running and never add water to acid.