Should I use Bromine or Chlorine in my Hot Tub?


Let’s face it, there is no better way to relax than in a Hot Tub in your back yard. Whether it is summer or winter, they are just perfect all year round. Regular maintenance is always necessary to keep the water sparkling clean. Chlorine and Bromine are the two most popular disinfectants for the job. Which one suits you or which one is best? In this article, you will learn the pros and cons of these chemicals so that you can make your your own informed decision.

What Is Chlorine?

You have heard of it, but what exactly does it do for your hot tub? In drinking water and even in paints and textiles, chlorine is the disinfectant that destroys bacteria. A chemical reaction takes place after chlorine is poured into the tub and the solution decomposes after a certain time to disinfect the water. Chlorine is available in various forms, such as tablets and liquids, although all have the same function, namely to protect the water from germs. Chlorine, unlike bromine, has a strong odor, but it is the most popular cleaning agent because it is easily accessible and can clean tubs within a few hours. Although chlorine is a popular choice, bromine is also an excellent option.

What Is Bromine?

Bromine is the number one alternative to chlorine. The reason that hot tub owners prefer bromine over chlorine is because it works better in warmer temperatures. The chemicals contained in bromine behave differently than chlorine, when destroying bacteria and pollutants. Like chlorine, it comes in several forms, in tablets and liquids, but never in its raw state. If it is in liquid form, it is diluted with water for safety reasons, as it is harmful to skin and eyes. Bromine and chlorine are very similar in that they both disinfect, but have differences in chemical degradation.

Shocking Procedure

Chlorine and bromine are used to disinfect hot tub water in different ways. Chlorine is an oxidizing and disinfecting agent. As soon as chlorine is added to the water in a shock treatment, it easily mixes with bacteria and kills them. Chlorine should be added approximately every two days. Bromine, on the other hand, is nothing more than a disinfectant. It takes longer to activate after it has been added to the water, but remains active even after the bacteria is dead. This means that you only need to add bromine once a week.


There are three different ways to add chlorine: in granules, liquid or tablets. Without special equipment, the granules or liquid can be added directly to the water, while the tablets are placed in a floating dispenser to maintain a sufficient chlorine content in the water. However, bromine is best dispensed through a floating dispenser or cartridge dispenser, which increases the initial cost of using bromine. One application of bromine can last up to a week, while chlorine should be applied approximately every other day.


A 20,000-gallon used year-round would cost about $600 per year for chlorine sanitation. If you use tablets, you would have to spend about $20 on a floating power supply to distribute the chlorine. The same water treated pool in bromine would cost about $1,000 per year. In addition, you may have to spend between $150 and $400 on a bromine feeder system.

Health Issues

When choosing between chlorine and bromine for your hot tub, cost is not the only factor to consider. For sensitive people, bromine is much safer because it is much less harmful to the skin and eyes. However, if a chlorine allergy is a problem, bromine does not work because it is also dependent on chlorine. The only remaining options are a peroxide based system or silver or copper based ion generators. Bromine does not give off the same strong smell as chlorine, but the same consistency that keeps it active in your hot tub makes it difficult to cleanse after soaking.

High Temperatures

Bromine works better than chlorine at higher temperatures. Bromine remains stable above 75° F, while chlorine is more effective at temperatures up to 65° F. It makes bromine a safer option for spas and hot tubs, and the use of chlorine would be better for an unheated pool.

Water Transparency

Chlorine oxidizes and removes not only bacteria but also organic matter, including body oils, from the water. In this way, the pool water remains sparkling. The lower pH value of bromine makes the removal of organic deposits less effective, resulting in a cloudier appearance. This requires an occasional chlorine shock to keep the water as clear as possible.

Pros and cons of chlorine and bromine

Both chlorine and bromine have their pros and cons, but how they work for you depends on your preferences and needs. Remember that if you are allergic to chlorine, bromine is not a suitable substitute because it belongs to the same chemical family.

Here are the pros and cons of using chlorine and bromine in your hot tub:



  • Easily accessible
  • Effectively kills or inactivates pathogens and algae
  • Wide range of applications (tablets, granules, liquids, gases, etc.).
  • Oxidizes materials in the water
  • Works with all three types of pools (except salt systems)
  • Maintains a residual concentration in the water


  • It can leave a strong smell
  • May cause eye or skin irritation
  • Salt-chlorine systems can wear away vinyl siding and concrete pools.
  • Vinyl linings may fade on prolonged contact (granules on the bottom of the pool).
  • Chlorinated products may contain other ingredients that dilute the amount of chlorine available.



  • Has no strong odor
  • Gentler to the eyes than chlorine
  • Effective disinfectant and algaecide
  • Acts as an oxidizing agent
  • Great for sanitizing hot tubs
  • Works with vinyl, concrete and fiberglass hot tubs.


  • More expensive than chlorine
  • Less oxidation power compared to chlorine
  • Not suitable for persons with a chlorine allergy.
  • Does not work well when exposed to sunlight


Both chlorine and bromine are excellent options for keeping your hot tub water clean. Their effectiveness should not be questioned. In the end, when choosing between chlorine and bromine as a disinfectant for your hot tub, you should consider not only the cost, but also the ease of use and safety concerns.


Can I Help You?

If I can help you in any way I would love to hear from you. You can get in touch using the form below.

Thanks - Andi


Hi, Andi here. I own and also write all of the articles and info pages on the site. Some years back now, I built my own hot tub but struggled to find the information I needed. So, once my tub was complete, I started this website to help others in their own pursuit of hot tub and plunge pools DIY building information.

Today, I've helped over 1000 DIY customers just like you all over the world build hot tubs and pools. Have a good look around the site, there are lots of resources here. Please do get in touch if I can help you. - Cheers, Andi

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