Bromine 101 – How To Use Bromine In A Hot Tub

Your spa water can be purified using various methods including bromine. You could opt for chlorine, bromine or the ozone system. All these chemicals can help you maintain a clean and sanitized hot tub.

In order to start using bromine in a hot tub, you can do the following:

  • Drain your hot tub
  • Refill the hot tub with clean, fresh water before adding the sodium bromide or bromine tablets to the water

If you’re using sodium bromide regular oxidation with ozone or using a spa shock system is important to turn the bromide into the sanitizing and effective bromine. For bromine to be effective, enough bromide ions must be present in the tub.

For perfect hot tub sanitation, bromine is preferred to chlorine and other hot tub sanitation substances. If you’re considering sanitizing your hot tub with bromine, here’s how to use bromine in a hot tub. From experience and universal reviews, using Bromine in your spa or hot tub is undefeated because it is effective and unlike chlorine, it does not leave your skin feeling irritated.

Bonus reading

Have You Considered Switching From
Chlorine To Bromine?

There’s been a trend where people are switching from chlorine to bromine. I feel there is not a lot of information about that transition and how to go about it since you can’t mix the two. I have addressed the most common misconceptions about this in the following article.

How Much Bromine Do You Put In A Hot Tub?

Maintaining a safe level of bromine in the water is important to avoid skin and respiratory system irritation. Here’s your guide to safely using bromine in your hot tub.

The ideal bromine level for a residential spa is four parts per million, but a range of 3.0 and 5.0 parts per million (ppm) is also safe and permissible. After applying the bromine tablets, test the water with bromine test strips to ensure its safety. This is an important step because high bromine levels are unsafe chemicals in the water.

I found the bromine test strips below to be really quick and easy to use. It literally takes about 2 seconds to shake it and to get the result.

LEISURE TIME 45005A Spa & Hot Tub Test Strips 4-Way Bromine Testers, 50 ct
  • BENEFITS: Helps you know any chemical imbalances in your spa or hot tub water so you can treat it appropriately
  • USE: Tests for pH, alkalinity, calcium hardness, and bromine or chlorine
  • COMPATIBILITY: Bromine or ozone systems
  • SIMPLE TO USE: Immerse the test strip in the water for 2 seconds, remove and shake off excess water; Easy to read immediately
  • INCLUDES: One container of 50 testing strips
  • Buy a bromine test strip from your local pool store (or order from Amazon) and follow the instructions on the package.
  • Dip the strip into your hot tub and wait for the chemical reaction which changes the color of the strip.
  • Compare the strip to the color code on the packaging for the product purchased to know the range of bromine present in the water.
  • High level of bromine in your hot tub signifies that it is not ready to be used.
  • It is advised to wait for a few hours or sometimes a day to allow the bromine level drop to the ideal range.
  • Testing the water in your hot tub indicates it safety or otherwise.
  • Then the hot tub fit for use.

The addition of bromine will depend upon usage, the quality of the water and bathing habits. It could be daily or every 2-3 days. Experts advise that for 3ppm add 12g per 1500 litres of water. Be sure to read the directions on the packaging of the bromine tablets you purchase to make sure you’re adding the right amount.


Have you gotten your hot tub accessories this year?

Honestly, when I experienced a hot tub for the first time, it was good enough for me. It hasn’t gone a lot before I thought how cool it would be to have a drink in my hot tub, watch a game or bring my food with me. I had no idea people already made things for your hot tub so you can do just that. I have a long list of hot tub accessories that might be interesting to you. Click here to read the article.

Do I Need Bromine In My Hot Tub?

Chlorine tablets for hot tubs tend to be harsh and cause skin irritation. Hence the use of bromine in spa water and hot tubs.

In case you are using chlorine now and wonder how often you need to add it to your water, I have a nice article that took me some time to research that can give you more information about using chlorine. You can read it here.

You need bromine in your hot tub because it is proven to be an effective sanitizer that destroys algae, microorganisms and hot tub bacteria.

If you use chlorine for hot tub, it exhibits weaker oxidation properties even though it might be faster but bromine has a larger molecular size which gives it an advantage at killing bacteria and viruses.

Bromine combines with bacteria in spa water to neutralize it even though a good portion of the bromine stays active even after combining with the bacteria. If your family has sensitive skin, bromine is obviously a better option to chlorine.

How To Build A Bromine Bank

Building a bromine bank ensures the effectiveness of bromine in the hot tub.

A bromine bank is a reserve of sodium bromide ions in the water. The sodium bromide dissolves into bromine via spa shock, ozone or liquid chlorine. (Links will take you out to recommended products on Amazon) The average sodium bromide tablets compose of about 30% chlorine and 70% bromine.

To successfully build a bromine bank, always add sodium bromide tablets after draining, shock the spa with your preferred oxidizer and this activates the bromide ions and converts it into hypobromous acid which is the killing form of bromine.

How To Shock A Hot Tub With Bromine

A hot tub shock is an oxidizer that activates bromide ions in the hot tub water with spa shock and converts them to hypobromous acid, the killing form of bromine.

While preparing to shock the spa water, you should first test and adjust the pH level to about 7.2 to 7.5. The shocks work in a low pH environment, and the efficiency of your spa shock is twice as great at a pH of 7.5 than it is at a pH of 8.0. Make sure to have a well-balanced pH level.

Here, the numbers behind a decimal point matter so you really want to have as accurate pH strips as it can get. I will share a whole kit with you below that’s on sale (at the moment of writing this) that’s really accurate in case you need to order it.

Invigorated Water pH Tester - Measures pH Levels of Water and Saliva - More Accurate Than pH Test Strips - pH Water Tester - pH Level Tester for Water - pH Tester Water Drops - pH Test Kit (3-Pack)
  • Quickly Understand the pH Scale of Water – pH PERFECT pH test kit will help you quickly determine the pH balance of water. Simply squeeze a few drops of pH PERFECT reagent liquid into a small sample of water and wait for the water to change color. Compare the water color with the included pH scale chart, to confirm pH levels.
  • More Accurate for Testing Water pH Than pH Test Strips – pH test strips are designed for testing the pH levels of saliva and urine to determine where it sits on the pH scale, not for testing the pH balance of water. pH PERFECT is the ideal & accurate pH tester for water.
  • Super-Sized Value 3-Pack – pH PERFECT includes three 0.33 ounce (10ml) bottles. Every time you test the pH levels of your water, or saliva, you’ll only need a few drops of pH PERFECT, making this value 3-pack super-long lasting.

To shock your hot tub with bromine:

  1. Make sure the hot tub is open and without its cover. This is an important step as it allows the chemical reaction to release into the air and eventually diffuse. You should also remove any other floating accessories on the surface of the hot tub water.
  2. Protect your eyes and hands. Wear safety gloves and goggles while handling shock.
  3. Check that your tub’s PH is between 7.2 and 7.5 as stated above (balanced or neutral PH). An imbalanced pH will affect the shock’s ability to work well.
  4. Turn off your spa jets but keep the circulation pump on a minimum.
  5. Choose your dose of shock according to the bromine tablet or granules you are using.
  6. After bromine shock, test the water before going into the hot tub again. Be sure to leave the tub uncovered after this process.

Can You Mix Chlorine And Bromine In A Hot Tub?

Both chlorine and bromine are strong oxidizers meaning they burn up organic matter in the water.

You shouldn’t not mix chlorine and bromine since that can cause a dangerous chemical reaction.

If you would like to change the sanitizing agent in your water, you need to drain, clean and flush your tub.

You should NEVER:

  • mix chlorine and bromine together in water as this triggers a dangerous chemical reaction.
  • mix them together in their dry state, especially the granule forms. This can also cause a dangerous chemical reaction and an unpleasant odor.
  • store them side by side. Even in their separate containers, this is dangerous as the fumes they give off can combine and become combustible. They can literally start a fire
  • use the same feeder for both chlorine and bromine granules or tablets.

Is Chlorine or Bromine Better For Hot Tubs?

This is a question in the heart of every hot tub owner who is considering switching from chlorine to bromine. What really makes bromine preferred? Which of these is really the best spa and hot tub sanitizer?

Here are a few reasons why bromine is preferred.

  1. Bromine tablets are stronger and much more stable in sanitized conditions. It has the strength to kill more bacteria and viruses than chlorine.
  2. Though bromide tablets are slightly more expensive than chlorine tablets, they can be reused over and over again because the bromine ions remain active until chlorine molecules which become inert after first use. Ultimately, bromide tablets save costs.
  3. Bromine is stable and hardly affected by pH swings. Its effectiveness does not depend on the pH level of the spa water. It also remains stable regardless of the temperature of the water in the tub. Chlorine in a hot tub is highly affected by pH.
  4. When any of these chemicals combine with either nitrogen or ammonia, they react and form new substances. The newly found substance with the chlorine reaction is responsible for the eyes and skin irritation while bromamines, on the other hand, continue to be active sanitizers without the smell or irritation.
  5. The smell of bromine is not as harsh as that of chlorine.
  6. Bromine is also low maintenance because it does not require to be added to the clean water as frequently as chlorine tablets for hot tub.

Bromine has a lot of advantages over using chlorine. It lasts longer and is much more effective than chlorine at killing bacteria, especially at high temperatures and high pH levels.

On the other hand, you generally need less chlorine than bromine in order to properly sanitize your hot tub.

If you haven’t read my other post on how much chlorine to use in a hot tub, you can head there to get more information.

In the meantime, I will share both of these (from top industry brands) products that will do the job right.

The maintenance of a hot tub depends on the frequency of usage, the water care system, the type of your hot tub and your preferred sanitizing and oxidizing agents.

Whatever sanitizing agent you chose to use, apply carefully and always follow the manufacturer’s instructions for optimal performance and product safety.

Is Too Much Bromine In A Hot Tub Bad?

Unless you want to drain your hot tub every time you use it, hot tub chemicals are needed and we have to use them. The thing is that some people’s skin might react differently to the presence of bromine and chlorine from the others.

Having too much bromine or chlorine might reflect negatively on your skin. It is important to know exact measure of bromine and chlorine that should go into our hot tub.

Bromine is amazingly effective in killing germs and bacteria when properly added to a hot tub. This means that the amount of bromine should be optimal to the amount of water in your hot tub.

When the bromine levels are too high, you might experience discomfort while sitting in your hot tub. It is known that high levels of bromine and chlorine will irritate people’s skin, eyes and respiratory system.

This further develops into bromine rash or bromine coughing. Bromine rash is following red itchy skin as well as red itchy eyes. Some people may experience problems with their lungs.

All these reactions can appear within minutes of entering your hot tub. Just something to watch out for if you have sensitive skin.

The most ideal bromine levels are between 3 and 5 ppm.

This will reduce a risk of experiencing any negative effects of bromine and chlorine.

How Many Bromine Tablets To Put In A Hot Tub

Those who just purchased their first package of bromine tablets are probably wondering how many and when to add those bromine tablets to their hot tub.

You should add 3 bromine tablets for every 300 gallons of spa water added every 5 to 7 days while maintaining bromine residual of 2 ppm.

You should be using a floating tablet feeder that should be set to obtain an active bromine residual of at least 2ppm.

Can I Crush Bromine Tablets For Hot Tub?

Some people prefer to crush their tablets.

Yes, you can crush 3 bromine tablets for every 300 gallons of water spa and add the “crushing” to the water.

When you add the bromine tablets to your spa water, it is actually in the form of bromide ions which doesn’t start killing germs and bacteria right away. It needs to be activated using an oxidizer to turn bromine ions into hypobromous acid. At this point, your crushed bromine tablets will start reacting and killing an organic contaminant.

How Long Should Bromine Tablets Take To Dissolve?

As I said before, bromine has a couple of stages to go through.

As bromine is added, it introduces bromine ions and there are no tests to determine the how much bromide ions are in it. The reason for this is because the one test that would measure bromide ions will also measure amounts of chloride ions. Since every water will have some amount of chloride ions, the test becomes inaccurate and unacceptable.

As long as you have at least 15 ppm or more of bromide ions in your spa water, all the chlorine you add afterwards will convert bromide ions into hypobromous acid (which is what actually is killing the germs), none of it will provide a chlorine residual.

Your bromine tablets, perform a slow release of bromine into the water, just like chlorine tablets.

Bromine tablets can take up to 7 days to dissolve and it is for all the aforementioned reasons where bromine reacts slower than chlorine when it comes to removing any residual.

Bromine Tablets Are Not Dissolving In Hot Tub

Check your pH, alkalinity and total hardness levels.

In case your hardness and pH are high, you will need to address this first before you can add your bromine tablets. Check to see if your heater has any forming.

This is usually the main reason why your bromine tablets wont dissolve.

With bromine, with new hot tub fills, you might need to shock your hot tub more often in order to keep the bromine levels up for a few weeks. This is only until you have enough ions in the tub.

What shocking will do for you, is that it will re-establish most of the used bromine.

Again, before you can get to this test, get your levels sorted. As a note, you should keep your calcium hardness between 50 and 150. Any levels above 400 are super high.

Bromine Tablets vs Granules For Spa

Bromine comes from the same chemical linage as chlorine, and is highly effective when fighting germs and bacteria.

Bromine relatively easily dissolves in water and comes in two shapes, as tablets or as granules. If you want to use tablets, you will need to place them in a chemical dispenser or bromine feeder whereas granular chlorine dissolves immediately in the water.

If you are going to pick bromine tablets, make sure not to mix bromine and chlorine tablets and don’t use the same dispenser.

The optimum bromine level should be between 3 and 5 p.p.m.

Can’t Keep Bromine Levels Up


I have a hot tub, with a capacity of approximately 1400 liters (about 370 gallons) that I filled 2 weeks ago.

I used the 3-step bromine method to add bromine to the water. My problem is that my bromine keeps going down to 0 or 1 and I need to shock the hot tub every day. Since it is summer, I use it almost every day for about 15 minutes.

What would be the best way to shock my hot tub. Should I use 6% bleach, or I should maybe try to use a 2-step bromine system?


Did you start the tub with pure sodium bromide or a mixture?

  • Yes, I started with pure sodium bromide.

What kind of floater are you using? (Some floaters can’t properly dispense bromine and maintain proper levels accurately)

How often and for how long does your hot tub circulate?

  • My circulation pump is always working.

Are you testing the bromine before or after you use it? (Your bromine levels should be around 4 to 6 ppm before you use it)

  • I am always testing before I use the hot tub, not after.

Is your hot tub exposed to sunlight, meaning do you use a hot tub cover? (It is a known fact that bromine cannot be stabilised against loss from UV light)

  • Yes, I usually leave my hot tub uncovered in a direct sunlight so that might be the reason.

Keeping your hot tub uncovered when not in used is the main cause of your bromine levels going down. Try to keep it covered when not in use.

Keeping your hot tub covered wild yield to many other benefits including your monthly hot tub costs.

Your hot tub should only be uncovered when in use and when shocking it.

What does bromine do in a hot tub

Bromine just like chlorine is a great hot tub sanitizer. Bromine works by combining with the contaminants forming bromamines. Although not as reactive as chlorine, bromine works by slowly reacting and keeping your hot tub healthy. 

Bromine also has a lower pH compared to a sanitizer like chlorine thus keeping the water more balanced. Bromine also doesn’t itch your skin like chlorine does therefore making it a great choice if you have a sensitive skin. 

After reacting with contaminants, bromine becomes less reactive but a shock can make it effective again.  

How to lower bromine in hot tub

Once in a while, you may overspill bromine in the hot tub. Too much of it in the spa could corrode the components of the tub or even irritate your skin. There are different ways you can use to lower the levels of bromine in the hot tub.

  • Dilute the water 

Depending on the amount of bromine, drain some of the water in the hot tub and refill with fresh water. For this process, you can also use a bucket to draw some of the water from the hot tub. 

After diluting, run the hot tub so that the water mixes correctly. Test the water for bromine levels and dilute again if need be. 

  • Use a neutralizer 

If you want to use the hot tub almost immediately, then a neutralizer is the best solution. The best neutralizer is sodium thiosulfate which slowly breaks down bromine in the water. 

  • Give it time 

If you aren’t planning to use your hot tub anytime soon, then you can give it time. Naturally, bromine will break down thus decreasing in amount over time. This is the best way to allow bromine levels to decrease without using any chemicals. 

Bromine hot tub danger

Even though bromine is considered a better sanitizer compared to chlorine, there are some dangers associated with its use. 

  • Health risks 

Continuous exposure to bromine can give you rashes, eye irritation, and respiratory problems. Ingestion of water containing bromine is also associated with hypothyroidism because it affects iodine absorption. 

  • Corrosion of the shell 

The other danger associated with the use of bromine is that it can cause corrosion on the shell. If you use the bromine floaters to dispense bromine, once it disinfects all the germs in the hot tub, the excess chemicals end up corroding your hot tub. Of course this means that the hot tub won’t serve you for as long as you envisioned.

Editorial Staff

I'm Adnan Sabanovic, the guy behind Hot Tubs Report. I've had a chance to enjoy hot tubs last few years and have really become interested in owning one of them. Nearly every weekend you'll find me spending time with my family or playing sports. If I am not doing that then I'm here writing about tubs on Hot Tubs Report. This blog is a research for my first hot tub which I decided to document and share publically so others can benefit from it as well.

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