Bromine
Bromine is a halogen sanitiser used in pool and spa water that forms hypobromous acid (HOBr) as its active disinfectant form.
Definition
Bromine is a halogen sanitiser used in pool and spa water that forms hypobromous acid (HOBr) as its active disinfectant form.
Typical Values: Hot tubs and spas: 3–6 ppm; Indoor pools: 3–6 ppm
In Plain Language
Bromine works similarly to chlorine but has key differences: it is more stable at high temperatures (preferred for hot tubs), it remains effective over a wider pH range (7.0–8.0), and spent bromine (bromides) can be reactivated by adding an oxidiser. Unlike chlorine, bromine cannot be stabilised against UV, making it impractical for outdoor pools in direct sunlight. Bromine target: 3–6 ppm (compared to 1–3 ppm for chlorine).
Why It Matters
Bromine is the preferred sanitiser for indoor spas and hot tubs. Its stability at high temperatures makes it more effective than chlorine in these applications.
Typical Values
Hot tubs and spas: 3–6 ppm; Indoor pools: 3–6 ppm
Last reviewed: 2026-06-01