Share This


Chlorine vs bromine – What’s best for my hot tub? (Comparisons, advice and more)

January 28, 2023

Estimated read time - 4.5 minutes

Author – Phil Sharp - Freelance Writer 

Learning about what chemicals a hot tub needs? No doubt you have come across the question, should I use chlorine or bromine?

Chances are, you'll be asking yourself 'What’s the difference between chlorine and bromine?' 'Why do you need to use chlorine or bromine?' or 'Bromine vs chlorine hot tub?'

Jacuzzi® Bromine Granules

These are all common questions to come up when you begin your hot tub buying journey.

In this article we will help you learn:

-The key differences between chlorine and bromine

-Chlorine or bromine - which is stronger?

-Alternatives to chlorine and bromine

-And more

Understanding the difference between chlorine and bromine will help you make a decision about which sanitiser is best for you and your hot tub.

Why do hot tubs need chlorine or bromine chemicals?

The key need for chlorine or bromine is to remove bacteria and pathogens that can cause illness or irritation after each use.

Water that’s not being replaced daily (emptied daily) in a tub needs to be kept balanced so you can enjoy your hot tub and stay healthy. 

What is chlorine?

Chlorine is a chemical sanitiser that is used by the hot tub industry to help disinfect water quickly. It comes in granular form or tablets and is added to the water in your hot tub to ensure that no bacteria and pathogenic microbes are forming.

When added to water, the chlorine reacts and creates hypochlorous acid. This mild acid is what attacks and destroys the bacteria that can cause illness and irritation.

What is bromine?

Bromine, like chlorine is a sanitiser and its main purpose is to sanitise the water for safe hot tub use. It's a more gentle approach to sanitation but will require more regular monitoring of balancing the ph and the sanitiser levels of the hot tub. 

Jacuzzi® hot tub aerial

Do I need chemicals in my hot tub?

The short and simple is yes.

Although many hot tubs come with additional clean water systems like the CLEARRAY® Active Oxygen Water system used by Jacuzzi® uses UV technology to neutralise waterborne pathogens to leave the water clean and clear.

Regularly maintaining chlorine or bromine levels is essential for safe hot tub water and healthy hot tub use.

It is really important that you don’t just put your faith in additional sanitisation functions. You MUST use chemicals. Without them you will only see your water go cloudy and develop hidden pathogens and germs that could cause serious ill health.

Is chlorine more reactive than bromine?

While both chlorine and bromine create reactions when added to water, chlorine does produce a faster and more aggressive reaction. 

Which is stronger in a hot tub – chlorine or bromine?

If we assume the most reactive and quickest cleaning element is the strongest, the answer is chlorine. Bromine is regarded as a more stable product that works in a slightly slower way.

Although there are not great differences between the two, bromine tends to be gentler and slower option for the water. Swimming pools are known to use chlorine because large volumes of people use pools and it reacts faster to bacteria in the water.

Can you mix chlorine or bromine in a hot tub?

No, you must choose one product or the other. Both are different sanitsers and must never be combined in a hot tub. They are designed to work on their own.

Can you use chlorine shock in a bromine tub?

We would recommend using non-chlorine shock in a bromine tub. Chlorine shock has the potential to create too much chemical reaction in the water.

Jacuzzi® hot tub waterfall

What are the alternatives to using chlorine or bromine in a hot tub?

Although the easiest and most commonly used sanitisers are chlorine and bromine, that’s not to say that there aren’t additional cleaning systems that could be considered.

Three of which are:

Ultraviolet (UV) system: These replicate the natural UV in nature (created by the sun) to alter the DNA of bacteria and viruses, thus neutralising pathogens.

Ozonators: This system release small doses of ozone – the same gas that protects the earth – into your hot tub. Although effective, this system can be very expensive.

Salt-based systems: Salt is the only system that eliminates the use of treatment by chlorine or bromine. That’s because salt is converted to chlorine or bromine. 

Chlorine vs Bromine hot tub summary

Here’s your at-a-glance summary of chlorine vs bromine. It’s short and sweet but really highlights what you need to know and what to consider using in your hot tub.

Chlorine in a hot tub

-Quick and effective.

-Produces hypochlorous acid to get to work on destroying pathogens and bacteria.

-Slightly stronger than bromine due to the acid creating reaction.

Bromine in a hot tub

-Long lasting and effective.

-Breaks up bacteria through ionisation.

-Kinder to skin with a lower pH.

Jacuzzi® hot tub near a pool


After reading this article, you should have a clarity on the key differences that set chlorine and bromine apart and the importance sanitisers have in keeping your hot tub water healthy.

Wondering what role ozone plays in a hot tub? Read this article to learn more.

Need to purchase or top up existing Jacuzzi® chlorine or bromine products? Browse our full range on Jacuzzi® Shop.