bromine vs chlorine hot tub

While hot tubs can be enjoyed throughout the year, they do require maintenance to stay sparkling clean. However, choosing between the two main types of sanitizing chemicals, chlorine and bromine, requires a lot of knowledge and consideration.

The question we get pretty often is,

Which of these chemicals is the right choice for my needs?

Let’s dive in and check out the pros and cons of each of these popular water-keeping chemicals!


Understanding the Overarching Difference

Bromine and chlorine work in unique ways to keep your hot tub sanitized.

Bromine is simply a sanitizer. Once you add it to the water, it takes a bit longer than chlorine to activate.

The great thing about bromine is that it continues to actively work, even once it has already killed bacteria.

Hot tub users often find themselves having to add less bromine compared to chlorine.

Chlorine is a sanitizer, as well as an oxidizer. When you add chlorine to your hot tub, it is a bit of shock treatment.

Once you add chlorine to the water, it attaches itself to bacteria and kills it quickly. That bacteria is then burned up before it exits through the filters. When you use chlorine, it works much faster, though you do need to add tablets to your hot tub more often.


Though chlorine works much quicker, bromine is far more stable in water, especially when the water is warm.

Chlorine dissipates much faster compared to bromine, meaning you will need to replace it fa more often. The exception to this rule, however, is ultraviolet (UV) light. UV light is bromine’s worst enemy. If you have a hot tub that is outdoors and you want to use bromine, you will want to make sure to keep the cover on when it is not in use. 

When it comes to chlorine, you can stabilize it with various types of conditioners to keep it working, even when temperatures are high. Bromine can’t be stabilized with anything, which makes it a bit harder to deal if your hot tub is in direct sunlight often.


Understanding how much sanitizer to add to your hot tub is equally important. To get the proper dosage, you need to know the size of your hot tub or how much water it holds. First, you must follow the instructions provided to you by the hot tub manufacturer. You’ll know if you have used enough of the particular chemical by testing the gauge to water levels.

For bromine, the ideal levels range from about 3 PPM to 5 PPM (parts per million), though 5 PPM is optimal. For chlorine, on the other hand, the ideal levels range from about 1 PPM to 3 PPM, though 3 PPM is optimal.

It is worth noting that you will need to use larger doses of bromine compared to chlorine to achieve peak cleanliness. Bromine also costs more than chlorine. Of course, you don’t have to use bromine as often as chlorine, so in the end, costs may even out. It also depends on how much you clean your water and the size of your hot tub.


Contrary to what some may thing, hot tub chemicals are safe when the proper amounts are used.

Of course, as with many things in life, some people simply react differently. 

Bromine is much gentler on the skin compared to chlorine.

If you’re someone who likes to have long soaks, though, bromine can also be much harder to rinse off. 

Chlorine is much harsher on the hair, skin, and eyes, especially when chlorine levels are much too high. When chloramine levels are high in the humid air are your hot tub, they can make breathing more difficult. In some cases, high chloramine levels have been known to cause asthma attacks. 

Chlorine also has a more noticeable smell compared to chlorine, though that smell is easier to get rid of after a good rinse.

For those with sensitive skin, we highly recommend bromine. It is a far better choice for people who use hot tubs regularly, or for those who have difficulty breathing. However, if you do have an allergy to chlorine, that is an entirely different story. 

Bromine is chlorine-based, meaning those with allergic reactions won’t be safe. In these special cases, we recommend silver/copper-based ion generators or peroxide-based systems. 


Chlorine goes through an oxidization process when it is working with your spa water. It helps to remove bacteria, as well as organic matter, including body oils that run off into the water. Chlorine works to keep water as clear as possible.

Bromine, on the other hand, is less efficient when it comes to removing debris, as it has lower pH levels. This means that your hot tub will probably have a cloudier appearance if you are only using bromine. For this reason, we recommend shocking your water with high ph level chlorine tablets every once in a while to keep it looking as clean as you possibly can.

Temperature Factors

Bromine is more ideal for high-temperature situations, such as hot tubs.

Bromine remains stable above 75-degrees Fahrenheit while chlorine is most effective in temperatures that run as low as 65-degrees Fahrenheit. 

This is why we see chlorine in pools more often than hot, though bromine is found in most hot tubs.

Bromine Vs. Chlorine – Which Should You Buy?

Both chlorine and bromine can be purchased in granules or tablets, though we recommend going with tablets. If you are searching for a chemical that is less irritating, has lower pH levels, and can keep your water chemistry balanced for longer periods at a time, we would recommend going with bromine tablets.

On the other hand, if you are looking to keep your water as clean and clear as possible, kill bacteria quickly, and keep your water chemistry balance, even when faced with UV rays, use chlorine tablets.

If you’ve used one of these chemicals in the past, have a bit remaining in the bottle but not enough to get the job done, and a new bottle of another chemical, do not ever mix them. They cannot be used simultaneously.  Find out why in our “mixing bromine and chlorine in hot tub” article. 

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