Bromine Or Chlorine For My Hot Tub? 4 Reasons Why Bromine Is Better!

Bromine Or Chlorine For My Hot Tub

I got a call from a friend, Petra requesting to know which of these two sanitizers would be best for her hot tub – bromine or chlorine. Well, I told her I’m using bromine but chlorine isn’t bad. However, the choice of using either bromine or chlorine for your hot tub is yours to make. Some companies would recommend chlorine, but there is a reason for that. It is important to know your “Why” before you decide on the one to use.

Chlorine is more volatile and reactive than bromine at low temperatures, while bromine is more stable at temperatures above 75oF. This is why bromine is more effective in a hot tub because it lasts longer than chlorine at a high temperature. But chlorine works better in a pool that runs at low temperatures.

But you know, you can’t make the choice when you don’t know what the two entails. So I know you might also want to know which would be best for you. Well, this piece is here to furnish you with the information; you would need to know about these two. Then you can go ahead to make your choice.

Difference between bromine and chlorine

Bromine is a chemical element that is reddish-brown. It comes with an atomic number of 35 and has Br as its symbol. Chlorine on the other hand is a more volatile chemical element with an atomic number 17. It has CI as its symbol. It has a yellow–green color at room temperature. Both chemicals are used as active ingredients for sanitizers.

The pros and cons of bromine and chlorine

These two chemicals are great sanitizers that help keep your hot tub free from bacteria and other contaminants. You might still be confused on the one to go for because their reactivity and stability are not enough factors to make a decision yet. It will be good to go through the pros and cons of the two sanitizers. Below are the pros and cons of bromine and chlorine:

The pros of using bromine

  • Bromine has a lower pH than chlorine; this is an indication that your overall water chemistry will be more balanced.
  • With the bromine having a lower pH, it means that there will be fewer adjustments to be made.
  • This chemical is more stable than chlorine, especially when used in warm water.
  • Bacteria are killed for a longer time by bromine when used in a hot tub than chlorine. Bromine lasts longer because of its stability.
  • Bromine is gentler on the body than chlorine.
  • Bromine will be a better choice for those with upper respiratory difficulties and sensitive skin.

The cons of using bromine

  • It isn’t as reactive as chlorine, so it kills bacteria more slowly than chlorine.
  • Ultraviolet light kills bromine more quickly than chlorine, so it is bad for outdoor hot tubs. You may consider using a shelter for your hot tub.
  • A larger dose of bromine will be required to achieve as much result as chlorine.
  • It might become difficult to wash away the chemical if you sit too long in it.

The pros of using chlorine

  • Chlorine is a very reactive element, so it kills bacteria and other contaminants as fast as possible. It is more reactive than bromine.
  • Applying too much chlorine in your hot tub will only take you draining your hot tub, and replacing it with fresh water. No long process.
  • Getting a good result from applying chlorine only takes the addition of a small dosage of it, unlike bromine that needs more quantity.

The cons of using chlorine

  • The pH environment of chlorine is high. As such, the water chemistry might be unstable.
  • Chlorine is one chemical that dissipates faster than bromine. So you need to replace it more often.
  • Chlorine can be hard on eyes, skin, or hair, unlike bromine. It becomes worse at a higher level.
  • It can bring breathing difficulties if it lingers in the humid air around the hot tub.
  • Chlorine usage isn’t safe with those with sensitive skin and upper respiratory health challenges.

How both chlorine and bromine work

The fact is that chlorine is the most used sanitizer for swimming pools. But bromine is a better sanitizer for hot tubs because of its stability. You might still want to educate yourself to make your personal decision whether to go for bromine or chlorine. So you should find out below how they both work. Now, these two sanitizers are added to the water in a hot tub to kill contaminants.

This is exactly how each operates:


This chemical ionizes contaminants (anything contaminating the water). It makes them part their chemical bonds. So, adding recommended quantities of it to the water in your hot tub makes it very active and working as it should even in the presence of bacteria and other yucky things.

In the process of its reaction, bromine produces its byproduct which is known as bromamines. Bromamines aren’t as poisonous as chloramines which are byproducts of chlorine. Bromine, though effective, takes off contaminants in a slower way. But it keeps the chemistry of the water a lot friendlier to the body.

Now, to get bromine working the way it should be as a sanitizer, you need to use enough of it according to the amount of water your hot tub holds. To find out the number of water your hot tub holds, you can do the following:

  • Check your purchase manual.
  • This can be the basic thing to do. Your manual is your guide; you would be told all things about your hot tub.
  • Google it with your serial number. You can find this out by doing a little research. You can get the model or serial number and look it up on the internet
  • Place a call to your spa dealership. You can call the dealer who bought your hot tub from for this information
  • Contact your hot tub manufacturer, When you can’t still get the exact information you needed from the above avenues; it might just be time to call the manufacturers for the information. Get their contact from their website or check if it came with the manual then contact them.
  • You can also do the simple calculation by yourself. Follow the guide below to calculate the volume of your hot tub.

How to calculate the volume of your hot tub

What you need: 1-gallon container, a stopwatch, and tap water.

Step 1: Turn the tap on and fill the 1-gallon container with water. Record the time it takes to fill the container.

Step 2: Empty your hot tub and refill it with tap water. Record the time it takes to fill the hot tub.

Step 3: Calculate the volume: multiply the time it takes to fill your hot tub by 1. Then divide what you get by the time it takes to fill the 1-gallon container.


If it takes me 2 minutes to fill 1 gallon and 800 minutes to fill my hot tub. The volume of my hot tub will be – (800 x 1)/2 = 400 gallons.

When you have the information, you can know the dose of bromine to add to the water in your hot tub. According to Aquatech, the recommended level of sanitizer in a hot tub is between 3ppm and 5ppm.

If you end up with too much bromine in your water, you can either outgas or dilute it with more water. You can also use bromine neutralizing products to reduce it. With bromine, you might need 1 dose of it. But you need to use it more often, and as such, the cost of using it is higher since you need to buy it more often as the quantity used at a time is larger.

The good thing about bromine is that it is skin-friendly. It is gentle on the skin. It is the best choice for people with sensitive skin as it isn’t harsh on the skin.


Chlorine on the other hand works by oxidizing bacteria and other contaminants. It invades and destroys them from the inside out. Its working is to dissipate and then turn to a byproduct which is known as chloramines. When this happens, there are remnants left. These leftovers are responsible for the stinky, repugnant, and stinging nature that comes with the use of chlorine in the hot tub.

With this, the effectiveness of chlorine will be affected negatively. So, the truth is to make sure that you don’t have these waste products in the hot tub. Moreover, you need to be adding chlorine to your hot tub regularly, maybe once a week.

If the chloramines become difficult to be cleared, you need to shock your hot tub (that is the use of a large dose of oxidizer to clean out your hot tub before using it again). You might even do this shocking regularly too, to keep your hot tub in pristine and top shape.

When it comes to effectiveness after use, chlorine kills bacteria and other contaminants more quickly than bromine. But it wears out more quickly and this means, one needs to replace it more often. This chemical isn’t quickly destroyed by ultraviolet light. So it can be used with an outdoor hot tub.

When there are more chloramines in your hot tub, then be battle-ready to fight more bacteria breeding and more algae growth.. The right amount for ideal use of chlorine is 1-3 ppm (parts per million). If one overuse chlorine then the remedies are; draining the entire hot tub and refilling with fresh water, or using chlorine neutralizers.

Safety rules for trying out chlorine and bromine

Can you mix chlorine and bromine in a hot tub?

This is a big NO! If you would want to experiment with these two chemicals to find out which will work better for you – bromine or chlorine, then you are still on the right path. But you would need to take precautions to avoid a dangerous reaction that might be harmful to you. The common safety rules are:

  • You should never use the same feeder for the two chemicals. Whether you have thoroughly clean out one of them, don’t use it for the other to avoid them reacting to one another. Get two feeders, one for each.
  • To avoid dangerous fumes that they both may give off, don’t store them next to one another. Even when you have them in separate containers.
  • Don’t even try to mix them even in their dry state. This might lead to a dangerous chemical reaction.
  • Never mix them in the water. If you need to try out the next chemical, then you should clean and drain the previous sanitized water out then do a line flush to clear all deposits and build-up.

My verdict on bromine or chlorine for your hot tub

As I have already stated above, I’m sticking with bromine to be better after trying out the two. The following were my findings and reasons for recommending bromine

Health reasons

When it comes to the use of chemicals, the first consideration should be its implication on the body. If it would affect the body negatively, then for me it is already failing. Both bromine and chlorine serve the purpose of killing the bacteria they were made for, but chlorine is harsh to the body (the eyes, hair, and skin). It can even bring more dangerous health issues like difficulty in breathing with the presence of chloramines. But bromine is milder on the skin and works better with sensitive skin. This was my first consideration for choosing bromine.

Working in high temperatures

When it comes to a high temperature which is associated with hot tubs, bromine works better than chlorine. Even at 75oF and above, bromine will still be stable. Chlorine works mostly at low temperatures which at least should be 65 degrees. So with this, bromine is a better option for a hot tub than chlorine.

Best for indoor hot tub

Chlorine is made mostly for outdoor pools since it doesn’t evaporate easily like bromine. But bromine works better without exposure to the sun. So, it is very clear that using bromine for your indoor hot tub will be very effective.

The stability

Bromine is more stable especially in warm water than chlorine. So, if you don’t joke with the pH balancing of your hot tub bromine would be your best bet.

How to use bromine in a hot tub

Like we discussed above, bromine is the better sanitizer for your hot tub. But for it to be more effective we need to ensure that there is a good amount of bromide ion in the water. However, we also need a regular shock of the hot tub to convert the bromide ion to bromine. With these tips in mind, you can follow these three steps to ensure you use your bromine sanitize properly.

  • Add sodium bromide anytime you drain and refill your hot tub. Follow the instructions on the package.
  • Shock the hot tub regularly after building the bromide bank to activate the bromine.
  • Then add bromine tablets to a floater and use them to maintain the bromine and bromide levels.

Can you switch from chlorine to bromine in a hot tub?

Yes, it is very easy to switch from chlorine to bromine. All you need to do is to drain and refill your hot tub. Then use bromine as described above. But don’t forget to replace your chlorine feeder or chlorinator with a brominator to avoid dangerous reactions.

How often do you put bromine in hot tub?

Generally, 2-3 days is okay. But it depends on how regularly you use your hot tub. If your hot tub is actively used every day, you might need to test and add bromine every 1-2 days. Note: For every 3ppm, you need 12g of bromine per 1500 liters.


The two most used sanitizers for a hot tub are chlorine and bromine, but the best from my observation is bromine. So you can stick with bromine just like I have done. But it is still okay if you would like to experiment with the two to find out which will work better for you. However, don’t forget to work by the rules as earlier stated for your safety.

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