Chlorine vs Bromine: Which Sanitiser Is Best for UK Hot Tubs?

Keeping your hot tub water clean and safe is non-negotiable. Without proper sanitisation, bacteria and algae can quickly build up, making your spa unsafe to use.

Two of the most common sanitisers for UK hot tubs are chlorine and bromine; but which one should you choose? Let’s compare them side by side.

Why Hot Tub Sanitisers Matter

Hot tubs are warm, enclosed environments – the perfect breeding ground for bacteria if left untreated. Sanitisers like chlorine and bromine work by:

Killing bacteria and pathogens
Breaking down body oils, cosmetics, and organic matter
Keeping water clear and safe

Choosing the right sanitiser will make a big difference to ease of maintenance, water clarity, and user comfort.

Chlorine for Hot Tubs

Chlorine is the most widely used sanitiser in pools and spas.

Benefits

Fast acting and powerful at killing bacteria
Readily available and affordable in the UK
Keeps water crystal clear when properly balanced
Easy to test and maintain

Drawbacks

Stronger chemical smell (especially at higher temperatures)
Can cause skin or eye irritation for sensitive users
Requires more frequent top-ups compared to bromine

Best for: Hot tub owners who want a cost-effective, reliable sanitiser and don’t mind a bit of chemical smell.

Bromine for Hot Tubs

Bromine is another effective sanitiser, often favoured for hot tubs because of its stability at higher temperatures.

Benefits

Works better in warm water (ideal for hot tubs)
Gentler on skin and eyes compared to chlorine
Less odour – no strong “swimming pool” smell
Longer lasting, so fewer top-ups are needed

Drawbacks

More expensive than chlorine
Slower to kill bacteria (though remains effective over time)

Best for: Regular hot tub users or those with sensitive skin who want a softer, low-odour sanitiser.

Chlorine vs Bromine: Side-by-Side Comparison

Effectiveness: Both sanitise well, but chlorine kills faster; bromine lasts longer.
Comfort: Bromine is gentler on skin and eyes.
Smell: Chlorine has a stronger odour; bromine is milder.
Cost: Chlorine is cheaper; bromine is pricier but needs less frequent dosing.
Best Use: Chlorine works well for occasional use; bromine is better for frequent spa users.

Which Sanitiser Should You Choose?

For most UK hot tub owners, the choice comes down to:

Chlorine if you want a low-cost, fast-acting solution and don’t mind the smell.
Bromine if you prefer comfort, less odour, and longer-lasting protection — especially for regular use.

Ultimately, both will keep your hot tub safe if used correctly. The “best” choice depends on your budget, sensitivity, and how often you use your spa.

Need Help Maintaining Your Hot Tub?

At Spafix, we service, repair, and maintain hot tubs across the UK. Whether you’re using chlorine or bromine, our engineers can help with: