A practical guide to bromine for hot tubs and spas. Learn what it does, how to use bromine tablets, how to test the water and how to fix common issues.
Bromine is a spa sanitiser used to keep hot tub water clean. Its main job is to kill bacteria and help prevent cloudy or unpleasant water.
In hot tubs, bromine is commonly added as tablets through a floating dispenser or spa feeder. It is a popular choice because it works well in warm water and keeps sanitising after it has reacted with contaminants.
Bromine helps destroy bacteria and organic waste introduced by bathers. This makes the water safer to use and helps reduce odours and water quality problems when the tub is maintained properly.
Many hot tub owners choose bromine because it is generally steadier in hot water than chlorine. It can also be a practical option for people who want an easy tablet-based routine.
Bromine tablets should usually be added through a floating dispenser or a built-in feeder, not placed directly into the hot tub water. Direct contact can damage surfaces or leave over-concentrated areas.
Start by making sure the water is balanced, especially pH and alkalinity, then add tablets to the dispenser and adjust the openings so the bromine level stays in the recommended range on your test kit. Check the level regularly and top up tablets before the dispenser runs empty.
Good bromine results depend on more than adding tablets. If pH or total alkalinity is out of range, the sanitiser may not work as well and the water may become uncomfortable to use.
Use spa test strips or a liquid test kit to check bromine, pH and total alkalinity. Make small adjustments, circulate the water and retest before making further changes.
If bromine is too low, the water can quickly lose clarity and sanitation. If it is too high, the water may become uncomfortable and you may need to reduce use until levels return to normal.
Most bromine issues come back to a few basics. Empty dispensers, poor water balance, heavy bather use or missed shock treatments can all affect performance.
It depends on your preference and maintenance routine. Bromine is widely used in hot tubs because it works well in warm water and is easy to apply with tablets.
No, they should usually go in a floating dispenser or feeder. Putting tablets directly into the water can damage surfaces and create concentrated spots.
Test regularly, especially when the tub is used often. Frequent testing helps you catch low sanitiser levels or water balance problems before they become bigger issues.
Cloudiness can be caused by low bromine, poor pH or alkalinity, dirty filters or a need to shock the water. Test the water fully and clean the filters before making further adjustments.
Expert guides on hot tub and pool water care, sanitisation, balancing, troubleshooting and seasonal maintenance from the ClearSpa team.