What chemical is commonly used to lower pH in swimming pools?

Muriatic acid, also known as hydrochloric acid, is commonly used to lower the pH in swimming pools because it effectively reduces high pH levels, which can lead to scaling and cloudy water if left untreated. Maintaining the correct pH level, ideally between 7.2 and 7.8, is vital for ensuring the effectiveness of chlorine in disinfecting water and for the comfort of swimmers by avoiding eye and skin irritation. Muriatic acid is a fast-acting solution that can be added directly to the pool water to achieve the desired pH level quickly. This makes it a common choice among pool operators for managing water chemistry and maintaining optimal swimming conditions. Other options, such as sodium bicarbonate, are used for raising pH, whereas chlorine and calcium hypo serve different purposes in pool sanitation and mineral balancing.