Bromine for Pools vs Chlorine

Bromine is far less common, but actually very similar to chlorine in a lot of ways with its own unique benefits. It is also used to sanitize and disinfect swimming pools and spas as a proven alternative to chlorine. What are the differences between using Chlorine vs Bromide in a swimming pool?

  • Chlorine(Cl) works faster to kill contaminants but for a shorter period of time, as it dissipates faster.
  • Bromine(Br) a more stable chemical kills contaminants more slowly but for a longer period of time & can help keep H2O chemistry more balanced due to its low pH, meaning less adjustment is needed.

Chlorine and bromine are the most widely available chemicals used for pool sanitation and treatment. Both are halogens and belong to the same chemical family. With the following pointers, you will easily understand the significant differences between them.

Bromide for Pools vs Chlorine


As pool season approaches pool owners look for alternatives to everyone’s number one concern when it comes to swimming pool chemicals and that’s Chlorine. There are concerns when it comes to using and storing chlorine granules tablets and shock chlorine on-site. Bromine and Chlorine: Which to Choose? - Pool and Hot Tub Depot

Difference Between Bromine and Bromide

Over recent years, one chemical has been accepted as a dependable alternative disinfecting agent chemical for use in swimming pools and Hot Tubs eliminating the need for chlorine. What is Bromide?

The key difference between bromine and bromide is that bromide is the reduced form of bromine.

Bromine is a chemical element with the symbol (Br) and atomic number 35. It is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly colored vapor. Its properties are intermediate between those of chlorine and iodine.

Chlorine to your swimming pool or spa, the chlorine molecules go to work right away attacking organic contaminants through a process called oxidation.

This means that chlorine attacks and literally steals electrons from whatever contaminants are in your pool, changing its molecular structure. Through this chemical reaction, chlorine leaves behind a waste product or residual called chloramines which is less effective in disinfection

  • Bromine, on the other hand, works by a process called ionization. bromine combines with bacteria but actually forces apart the chemical bonds of the contaminant. Bromine also has a lower pH than chlorine and most importantly even after bromine has sanitized the water, it is still active and continues to work in the pool.
  • Bromamines continue to be ready sanitizers, unlike chloramines
  • Bromamines don’t gas off the pool water surface as readily as chloramines
  • Bromine has a pH balanced, unlike the very high pH of liquid chlorine
  • Bromine remains a stable chemical at higher temperatures
  • Bromide ions can be activated into Free Bromine, by shocking
  • Bromine is gentler than chlorine on the skin, hair, and eyes

When it comes to bromine, it does not have a strong scent, it’s gentler on the swimmer’s skin, does a great job sanitizing high-temperature swimming pools, and works well without damaging vinyl liners.

Swimming Pool Care Chlorine


Chlorine is added to the pool water to kill bacteria. But it does not work right away. If used properly, free chlorine can kill most germs within a few minutes. Center for Disease Control(CDC) recommends pH 7.2–7.8 and a free chlorine concentration of at least 1 ppm in pools and at least 3 ppm in hot tubs/spas.

If using cyanuric acid, a chlorine stabilizer, or chlorine products with cyanuric acid (for example, products are commonly known as dichlor or trichlor, CDC recommends pH 7.2–7.8 and a free available chlorine concentration of at least 2 ppm in pools. CDC recommends not using cyanuric acid or chlorine products with cyanuric acid in hot tubs/spas.

The best way to kill germs is by properly maintaining the free chlorine concentration and pH. To do this, pool and hot tub/spa owners must routinely test and adjust both the free chlorine concentration and pH. Since a few germs can survive for long time periods in even the best maintained pools. Combining good chlorine and pH control and encouraging swimmers to follow the healthy swimming steps will help prevent the spread of germs that cause swimming-related illnesses.

Chlorine is a chemical sanitizer that typically comes in either tablet, powder, or liquid form, which is then prepped and added to your swimming pool in order to keep your pool water clean and safe to swim.

Chlorine is a safe chemical that keeps us healthy by killing germs in the water. But misusing chlorine can be risky. When you mix chlorine with other chemicals, compounds can be created turning into toxic vapors.

Chlorine developed for pools and spas protects us from germs and micro-bacteria. Chlorine has been effective against health conditions like diarrhea or a swimmer’s ear for years. Using guidelines controlling pH and chlorine constitutes the first line of defense against contaminated waters.

Chlorine can be applied to pool water in three ways tablets, liquid, and granules. Liquid and granules can be directly added to water without using specialized equipment. And, the tablets are dispensed through a floating feeder to maintain the chlorine level in the water.



Pool Bromine Pool Care Tips


A sanitizer deactivates/kills pathogens, ie kills bacteria and renders viruses harmless. An oxidizer breaks down organic waste products, like ammonia, into their components. Bromine is, like chlorine, both a sanitizer and an oxidizer.

The flow of pool water through the Brominator results in the dissolution of the tablet to produce a solution of bromine which can then be fed to the cooling water system and process system where micro-biological control of micro-organisms is required.

Above 75°F, bromine remains stable, whereas chlorine is more effective in temperatures as low as 65°F. This makes bromine a better choice for hot tubs and spas, and an unheated pool will be better served by the use of chlorine. Chlorine oxidizes when it is working, removing bacteria and organic matter such as body oils from the water.

Chlorine and bromine are sanitizers that help keep your pool or spa water clean and safe. Both chlorine and bromine come in tablet and granular form, while chlorine is also available in liquid form.

Like chlorine, bromine is another naturally occurring element. At room temperature, it turns into a liquid. It dissolves in H2O with a bleach-like odor. One significant difference between chlorine and bromine is you would not use bromine to disinfect drinking or cooking water.

Hayward Pool Brominator

There are many uses for Bromine. It’s an oxidizer, pool sanitizer, and algaecide. Many spa, pool, and hot tub owners use bromine instead of chlorine. One of the main reasons is that bromine works better under warm temperatures than chlorine.

  • Bromine cannot be stabilized from the sun and slowly depletes in bright sunshine
  • Bromine is more expensive, expect to pay 25% more than chlorine sticks
  • Bromine must be dispensed in a Brominator, and never in a used chlorinator

A Brominator works with Bromo chloro-dimethyl hydatoin to keep your system sanitized. Using a Brominator works better than chlorine.

The chemical that is created called hypobromite, will keep your water clear and free from algae and it will not leave a chlorine smell.

Chlorine works well indoors and outdoors, but bromine is sensitive to sunlight and less effective when exposed to UV rays. In fact, according to the NSPF, half of the pool bromine can be destroyed by exposure to sunlight in just 60 to 90 minutes. Unlike chlorine, cyanuric acid that’s added to chlorine products does not protect bromine from the sun.

Cost of Chlorine Compared to Bromide


The advantage of using chlorine over Bromide is the price. It’s more expensive than chlorine which is why people tend to overlook it. However, since maintaining your pool requires less volume of bromine, the cost difference actually isn’t all that drastic.

Since the bromine lasts longer than the chlorine, you need much less of it to clean a pool. Even with the fact that you need less, bromine is still a much more expensive way to sanitize your pool than chlorine is. When considering the difference between bromine and chlorine, just remember that the hot tub smell and the way bromine lingers clearly show the difference between the two. Finally, Bromine is unstabilized which means sunlight will chew through it much faster than stabilized chlorine, which is also why it’s typically Bromide Santizer used for indoor pools and hot tubs.

Bromine Use in Hot Tub


Bromine remains stable at higher temperatures than chlorine, which is why it is popular in hot tubs. The chemical composition of bromine reacts differently than chlorine and cleans water more efficiently in hot temperatures. It is worth noting that bromine will deplete UV rays more rapidly than chlorine due to the product having little UV protection.

Bromine can be used to keep spa water sanitary and is gentler on a user’s skin than chlorine. It’s also really easy to get started and maintain your system.

  • Start by flushing, draining, and refilling your spa with fresh, clean water.
  • Then, add sodium bromide to the water to build up a reserve of bromide.
  • Use a spa shock treatment to activate the bromide and turn it into the sanitizing bromine.
  • To maintain the proper levels, test the water with bromine test strips, float bromine tablets on the water, and shock the water in the hot tub/spa regularly.


Cost Comparison of Bromine vs. Chlorine


One of the main reasons most pool owners opt for chlorine as a sanitation product over bromine is the cost. Bromine is a much more expensive product, and pool owners can expect to pay up to double the cost of chlorine for it. For example, a 50-pound bucket of chlorine will usually cost around $150, while a 50-pound bucket of bromine will cost about $300.

First things first, let’s cover the basics. Chlorine and bromine are sanitizers that help keep your pool or spa water clean and safe. Both chlorine and bromine come in tablet and granular form, while chlorine is also available in liquid form.

Which is more toxic chlorine or bromine? Concentrations were based on the estimate that bromine is 1.5 times less toxic than chlorine.

Understanding how each sanitizer works is key to deciding the best option for your pool or spa. While chlorine and bromine clean your pool, they do so differently.

Bromine has a long shelf life and dissolves slowly. In some applications, it’s activated with an oxidator. The solution will last longer than chlorine. If your water is outdoors, you’ll need a cover as bromine has no defenses against UV light. UV light kills bromine faster than it does chlorine.

Chlorine vs. Bromine: Health Concerns


As long as you use these elements in proper amounts, both bromine and chlorine are considered safe. Chlorine can create difficulty breathing, sore throat, wheezing, coughing, chest tightness, eye and skin irritation, and other conditions. Most conditions result from ingesting heavy amounts of chlorine into the body, which you’re likely at low risk of in a pool.

Chlorine also contains bleach, has a distinct smell, and can irritate the skin. On the other hand, bromine is widely known for having an imperceptible odor. Pool water treated with bromine has fewer bad eye or skin reaction reports. And since bromine has no bleach, water has less effect on clothes.

When not used safely, breathing in bromine gas can give you a headache, watery eyes, and irritate mucous membranes. Getting bromine gas or liquid on the skin can cause irritation and even burns.

Irritation and allergic reactions can occur after exposure to both chlorine and bromine. However, according to the national swimming pool foundation (NSPF), bromine is better for individuals with sensitivities. It does not emit a strong smell like chlorine and its byproducts are like chloramines. But due to its stability, it’s harder to rinse off your skin after a swim.



What are the Advantages of Bromine in Pools?

Bromine advantages:

  • Does not give off a strong smell
  • Gentler on eyes than chlorine
  • Effective disinfectant & algicide
  • Acts as an oxidizer
  • Works with vinyl liner, concrete, & fiberglass pools
  • Bromine works in warmer temperatures
  • Keeps H2O chemistry balanced due to its low pH..………………………………….. Read more



JimGalloway Author/Editor


References:  CDC-Water Testing and Testing Difference Between Bromine and Bromide



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