Which is more effective for a hot tub, chlorine or bromine?

Which is more effective for a hot tub, chlorine or bromine?

Hot tub users may find it difficult to agree on which sanitizer is the best based on factors like strength, stability, convenience and most importantly and constantly asked, is it cost-effective?

Would you agree? Should you use chlorine or bromine for your spa's sanitizer?

Each product has defined qualities and advantages. Nevertheless, selecting the perfect sanitizer for your tub’s filtration system is vital.

Before we establish which hot tub, sanitizer is the best, let’s challenge each other’s product features, benefits, and downside.

What it does

It is true that both chemicals remove contaminants from spa or pool water, but they do so in different ways and over different periods of time.

Bromine. It eliminates impurities through ionization. This process produces bromanine molecules, which continue to cleanse the water after ionization, by attacking and dismantling the polluting molecules. Compared to chlorine, it operates more slowly yet continuously. Due to its low pH, it aids in maintaining a more balanced water chemistry. Since bromine dissolves slowly, it takes longer for a residual to build up in the water and is challenging to immediately raise if the level drops. If you need to fast raise your bromine levels after a sudden decline, a bromine booster is a fantastic tool to have on hand.

Chlorine. It works as an oxidizer, destroying and eliminating impurities more quickly for a shorter amount of time as it evaporates more quickly. While chlorine work is in progress, its chemical reaction results in chloramines, which give the water in hot tubs an unpleasant smell. You will need to regularly add chlorine. Typically, once a week, to keep chloramines away. However, if the situation worsens and chlorine is failing to effectively remove chloramines, you can shock your tub.

But hold on! How many different kinds of chlorine are there?

Chlorine comes in different forms, but not every type is suitable for hot tub use. You must proceed with caution and be aware that utilizing the wrong kind of chlorine will have an impact on your water's chemistry and more. Your spa's components could be damaged.

Its form and power

Tablets, sticks, and granules are the three types of chlorine that are most widely used. It is possible to use tablets or sticks in floating dispensers, in-line or off-line chlorinators. They can be put in a skimmer, an automatic chlorinator, or a floating feeder to gradually dissolve over time, making them the choice that requires the least amount of maintenance.  A spa’s optimal chlorine concentration requirement is 2-5 ppm. Pre-disposing granular chlorine in a bucket of water is necessary prior to applying it to your spa/pool.

With a speedier oxidation process, chlorine is a more potent halogen. It is a more powerful disinfectant and can be protected from UV rays by stabilizing it with cyanuric acid. Therefore, outdoor pools are more likely to have it.

Bromine, however, has fewer forms and is disseminated in your spa or pool in a different manner than chlorine. Only tablets and granules of bromine are available, and they function best in a floating dispenser. In in-line or off-line chlorinators, bromine tablets don't perform as effectively since they dissolve more slowly than chlorine tablets do. A concentration of 4-6 ppm of bromine is ideal. Unlike chlorine, bromine does not clean and operate. It is an excellent choice for hot tubs since it works considerably longer with the same quantity of chemical, has a lower pH that will assist keep your water balanced more effectively, and is much more stable under higher temperatures. Warm water keeps bromine stable, and an electric shock can be used to reactivate the chemical in bromine pools and spas.

Adding bromine in a hot tub Stabilized chlorine tablet


Cost is the primary factor in why bromine rarely gets used as often as chlorine. Chlorine prices can range from a few cents extra to double depending on where you get it. Many pool owners are typically discouraged from putting it in their pools by the cost, but spa owners might choose to use bromine instead. A spa just requires a fraction of the chemical that a pool does.

Whereas, the 1" size of trichlor chloride tablets costs approximately twenty percent less than bromine tablets. When purchased in bulk, the 3" medications are nearly 40% less expensive. Chlorine does, however, have a shelf life, and, depending on the temperature at which it is kept, it may lose half of its potency after about a year.

Final thoughts

In the end, the choice between chlorine and bromine when sanitizing an indoor or outdoor spa depends on your personal situation. It is true that they are both good sanitizers, but they do so in different ways, each with their own ideal working conditions and advantages. Whatever the case maybe, it is always the rule of thumb to remember to keep your levels where they should be and your water balanced by keeping in mind the basic principles of spa cleaning upkeep.