What strength is muriatic acid used in pools?

Muriatic acid, also known as hydrochloric acid, is commonly used in pools to lower the pH level of the water. The strength of muriatic acid used in pools can vary, but it is typically around 31.45%, which is equivalent to 12.5 moles per liter (M) of hydrochloric acid.

It's important to use muriatic acid with caution and to follow the manufacturer's instructions for proper handling and dilution. The strength of the acid and the amount needed to adjust the pH level will depend on the specific pool and the current pH of the water.