You want to change the alkalinity of your hot tub water will muriatic acid be best choice?

Muriatic acid should not be used to change the alkalinity of hot tub water. While it can effectively lower the pH of the water, it is a strong acid and can be corrosive to the hot tub's components, such as the heater, pump, and plumbing. It can also cause skin and eye irritation.

Instead, it is recommended to use a pH adjuster specifically designed for hot tubs, such as sodium bicarbonate (baking soda) to increase alkalinity or sodium bisulfate (dry acid) to decrease alkalinity, These products are designed to safely and effectively adjust the pH level of hot tub water without causing corrosion or irritation.