Chlorine vs Bromine

Both chlorine and bromine are used to help keep pool and hot tub water clean by killing bacteria. But the big question is “Which one should I use?” While only you can decide, we’ll give you an overview of each.


chlorine vs bromine
How It Works: Chlorine for hot tubs comes in powder form (sodium dichlor). Chlorine for pools (sodium trichlor) comes in tablets. Most chlorine variants come stabilized via cyanuric acid. This makes it much better for outdoor use than bromine because stabilized chlorine is protected from the sun’s UV rays. When chlorine combines with water it forms hypochlorous acid, which is a mild acid that is excellent at killing algae, viruses, bacteria, and toxins from human sweat. As the chlorine dies, the chlorine turns into a gas. Yep, the nostalgic hotel lobby swimming pool smell is dead chlorine and needs to be treated with fresh chlorine.

Maintenance: Containers of chlorine granules and liquids should be stored away from sunlight in a dry, room temperature place. Its shelf life is about 5 years for granules and tablets. On average you’ll need between 1-3 ppm (parts of chlorine to one million parts water) to keep your pool or hot tub clean. While chlorine is cheaper than bromine per ounce, it also has less of a chemical odor.


How It Works: Bromine is commonly found in the earth’s crust as sodium bromide and potassium bromide. It typically comes in tablet and powdered form. On average you’ll need 3-5 ppm. When bromine combines with water it forms hypobromite. Bromine is not as reactive as chlorine, therefore it’s more stable than chlorine in hot temperatures, takes longer to dissolve and works for a longer period of time than chlorine. It costs only a bit more than chlorine granules, but also has a stronger “aroma” than chlorine. Be cautious; some studies indicate if you have exposure to bromine for long periods, you may experience negative effects on your health. Certain hot tub companies may void your hot tub’s warranty for using bromine tablets.

Maintenance: They absolutely must be stored in a cool, dark, dry environment and must be kept in an airtight container. When exposed to high humidity and heat it will release in gas form and/or deteriorate its own container. It’s average shelf life is five years.

***Various forms of bromine is banned in certain countries. Check your local laws.***

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