Spa owners usually choose one of two chemicals to sanitize their hot tub: chlorine or bromine. Both of these are classified as halogens and belong to the same chemical family. They have similar properties and both sanitize and oxidize contaminants in the water. However, they differ in how they do this and bromine often performs better in a heated environment. It is helpful to understand how these substances work so you know how to keep your spa clean and functional.
How Chlorine and Bromine Work
Chlorine uses oxidation to clean the water in your spa. The chemical steals electrons from contaminants and changes their molecular structure. This leaves behind a byproduct called chloramine, which is what causes the distinct smell we associate with chlorine.
Bromine is a chemical that is found in the earth’s crust as either sodium bromide or potassium bromide. When bromine is added to water, it uses ionization which forces apart chemical bonds of contaminants and produces broamines. These substances do not produce any odor and are easier on your eyes and skin.
Chlorine vs Bromine in your Spa
Spas operate at a temperature range of 96°F–104°F. This heat, coupled with jetted water, can create an environment where microbes flourish, unless steps are taken to prevent this. The higher water temperature can also cause rapid changes in water chemistry and affect pH levels.
Bromine performs better and remains more stable than chlorine in heated spa water. It is also less reactive to changes in pH. This is important because multiple people using the spa at the same time can cause swings in the pH level. Chlorine does not perform as well in this scenario. If the pH levels go above 8.0, chlorine can become sluggish and its efficacy drops below 50%, unlike bromine.
Another benefit of bromine vs chlorine for spa maintenance is that the broamines that are produced retain their killing power. These can be reactivated by using a non-chlorine shock. Chloramine cannot be reactivated and is burned out once it is used and is removed from the water.
However, there are some downsides to bromine. It is more expensive than chlorine, and you also need to use more of it to effectively sanitize your spa compared to chlorine. The best bromine level in your spa is three to five parts per million (ppm), whereas chlorine is 1.5 to 3 ppm. However, because bromine dissolves and is burned off less quickly than chlorine, it works for a longer period of time. This helps even out the cost difference over time.
Build a Beautiful Inground Spa
Pools by Design has been building luxury pools and spas in Tucson since 2009. We consider form and function to create a gorgeous custom oasis that you can enjoy for years to come. There are many features available that can make maintenance easier, including pool and spa automation systems that monitor the level of different chemicals.