Which chemical is NOT used for disinfection in swimming pools?

The correct choice identifies muriatic acid as the chemical that is not typically used for disinfection in swimming pools.

Chlorine and calcium hypochlorite are well-known disinfectants. Chlorine is the most commonly used chemical for maintaining water quality in pools, effectively killing bacteria and other pathogens. Calcium hypochlorite, a compound that releases chlorine when dissolved in water, also serves as a potent disinfectant and is often used in granular form to treat pool water.

Sodium bisulfate is primarily used to lower the pH levels of pool water rather than for disinfection. While it is critical for maintaining balanced water chemistry and preventing issues related to pH imbalance, its role is not directly associated with killing pathogens.

Muriatic acid, on the other hand, is a form of hydrochloric acid and is primarily used for adjusting the pH of drinking water and swimming pool water. It plays an important role in managing acidity levels but does not have disinfectant properties like chlorine or calcium hypochlorite. Thus, its primary function does not align with the disinfecting needs of swimming pools.