Caustic soda (sodium hydroxide) is used in water treatment to adjust pH levels, remove heavy metals from water, and soften water by removing calcium and magnesium ions. It is also used to control the alkalinity of water, which helps to stabalize pH levels and protect piping.
It is also used to remove hydrogen sulfide, a gas that can form in water systems and cause offensive odors and tastes. Caustic soda is an effective and economical treatment option for many water treatment needs, and is available in a range of strengths and grades.