What disinfectant is mainly used in spas?

Bromine is primarily used as a disinfectant in spas due to its effectiveness and chemical properties that make it suitable for warm water environments. Unlike chlorine, which can be harsh and cause skin and eye irritation in higher concentrations, bromine is gentler on the skin and eyes, making it a more comfortable choice for users in a spa setting.

Bromine remains effective across a wide pH range and is stable in warmer temperatures, which is essential in spa environments where water temperatures are typically higher than in standard pools. Additionally, bromine forms bromamines when it reacts with organic matter, and these compounds still retain disinfecting properties, which is beneficial for maintaining water quality.

Though alternatives like chlorine, iodine, and hydrogen peroxide can also be effective disinfectants, they do not provide the same level of comfort and stability in the unique conditions of spa water systems. Chlorine, for example, can produce irritating chloramines and is less stable at higher temperatures. Iodine is less commonly used in modern spa disinfection because it can stain surfaces and is limited in effectiveness at higher temperatures. Hydrogen peroxide is an effective oxidizer but less commonly used for continuous disinfection in spas compared to bromine.