CliniPool / Understand your water
Bromine: the champion sanitiser of hot water
- Bromine is a sanitiser close to chlorine, but far more stable in hot water (hot tub, indoor pool).
- Usual ideal range: around 4 to 6 ppm (mg/L).
- Big advantages: effective at 37 °C, far less smelly, tolerates pH swings better.
- Limits: more expensive, no UV protection (poorly suited to an outdoor pool in full sun).
Bromine is chlorine’s discreet cousin — and the undisputed champion of hot water. It sanitises on the same principle, but with three superpowers that make all the difference in a hot tub and an indoor pool: it stays effective at 37 °C where chlorine runs out of steam, it’s far less smelly and irritating, and it tolerates pH swings better. Its ideal range: around 4 to 6 ppm. Its main limit: it has no UV protection, which makes it poorly suited to an outdoor pool in full sun. The CliniPool app handles bromine like chlorine: tell it your sanitiser, and it sets its targets and doses to it.
Why it shines in hot water
Chlorine has an Achilles’ heel: above 30 °C, it degrades fast, and its protector (stabiliser) doesn’t work indoors. Bromine, by contrast, keeps its effectiveness at a hot tub’s temperature (37 °C) without flinching. Better still: its “spent” compounds — the bromamines — barely smell and barely irritate, where chlorine’s chloramines reek and sting the eyes in an enclosed space. For a covered hot tub or an indoor pool, it’s night and day on the comfort front.
Another practical asset: bromine is more forgiving with pH. Water whose pH drifts a little keeps bromine largely active, whereas chlorine nods off as soon as the pH rises.
The flip side
Nothing comes free. Bromine costs more than chlorine per volume treated, which weighs little on a hot tub’s small volume but becomes noticeable on a large pool. Above all, it has no UV protection: no equivalent to stabiliser, so outdoors under the summer sun it burns off at full speed. That’s why bromine reigns over the hot tub and indoors, and leaves the outdoors to chlorine (or salt).
A small operating point: bromine can partially regenerate with an oxidiser (a regular shock “reactivates” some of the already-used bromine), which optimises its consumption. The app builds this logic into its hot tub maintenance plan.
Bromine day to day
Maintaining bromine water follows the same philosophy as chlorine — test regularly, keep the sanitiser in range, watch the pH — with two nuances: the target is a touch higher (4-6 ppm) and the testing rhythm tighter in a hot tub (small volume, hot water, everything moves fast). The app sets all this automatically as soon as you tell it your pool runs on bromine, and calculates doses with YOUR product.
In one sentence
Bromine is chlorine that loves heat and hates odours: the natural choice for the hot tub and indoors. To find out whether it’s right for you (or to compare with chlorine and salt), the “chlorine, salt or bromine” guide helps you choose — and the app handles whichever sanitiser you settle on.
Frequently asked questions
What's the right bromine value?
The usual range sits around 4 to 6 ppm (mg/L) in a hot tub as in a bromine pool. It's a touch higher than chlorine, because bromine is inherently a little less 'biting' — but far more stable. The app sets the target to your pool.
Does bromine smell less than chlorine?
Yes, clearly. Its 'spent' compounds (bromamines) are far less smelly and irritating than chlorine's chloramines. It's one of the reasons for its popularity in hot tubs and indoors, where odours build up.
Can you use bromine in an outdoor pool?
It's possible but rarely optimal: bromine has no UV protection (no equivalent to stabiliser), so in full sun it burns off fast and gets costly. Its natural home remains the hot tub and the indoor pool.
Can you mix bromine and chlorine?
Never in the same feeder or in direct mixing: the reaction can be dangerous. Switching from one to the other is done cleanly, equipment rinsed, ideally at a water change.