Sanitisers: Chlorine v’s Bromine – which one should you use?

Sanitisers: Chlorine vs Bromine – Which One Should You Use?

When everyone talks about sanitisers for their hot tubs and a varying range of hot tubs at that, the default conversation is centred around chlorine, but what about the alternative chemicals that are available to create crystal clear spa water and not forgetting swimming pool too who can also use bromine?

To help you make sure you are choosing the correct sanitiser for your hot tub, one of our water management experts has highlighted the benefits, features and drawbacks of using both chlorine and bromine chemicals below. After all, no one wants to share their hot tub with the somewhat awkward and unwanted guest… bacteria.

How do chlorine and bromine sanitisers work?

Both sanitisers work by killing the bacteria in your hot tub water, but they do this in slightly different ways. Firstly, let’s look at chlorine.


Chlorine works by actively destroying any contaminants in the water of your hot tub. Whilst it breaks down the bacteria from the inside out, it dissolves in the water to form a waste product called chloramine.

By adding chlorine in your hot tub at least weekly, you will be able to keep chloramine at bay. You will know if you have a surplus of chloramine in your hot tub water as this is the chemical that has the notorious reputation for its unique smell, for causing stinging in the eyes and for drying the skin.

If the chlorine that you are adding as your hot tub sanitiser needs a helping hand, you can eliminate the number of chloramines in your water by doing a chlorine shock treatment. To help keep your water crystal-clear and ready to use, you will want to do this chlorine shock treatment regularly.  There are two types of shock which we will cover in our next blog, but calcium hypochlorite and an oxidising shock call Non chlorine shock granules.

Chlorine, here’s what you need to know.

·        The ideal chlorine levels in your hot tub water is 2-3ppm (parts per million), with 3ppm being the optimum reading

·        Can be purchased as chlorine granules or as chlorine tablets

·        Kills the contaminants in your water quicker than bromine

·        Test the levels of chlorine in your water using chlorine 3in1 testing strips

·        When chloramine levels are too high, it can cause itchy/stinging eyes, harsh/dryness on the skin and produce unique ‘chlorine’ smell

·        Chlorine dissolves quicker than bromine, and as such should be added more frequently to your hot tub to maintain perfectly balanced crystal-clear water.

· You can add chlorine granules direct to your spa, hot tub water and don’t forget your PPE and always follow the manufacturers guidance


Bromine on the other hand works by forcing apart the chemical bonds of the contaminants in your hot tub water and as it dissolves in the water it remains active, continuing to work even when it has combined with the unwanted particles.

Unsurprisingly (and like its cousin chlorine), bromine also produces a waste product which is known as bromamine. However, bromamine is not known to have as many side effects when present in your hot tub, but it will reduce the efficiency of your bromine sanitiser. If you are using bromine in your hot tub as your sanitiser of choice, you will want to test the chemical levels regularly and undertake an oxy-shock treatment if the levels need adjusting.

Bromine, here’s everything you need to know.

·        The ideal bromine level in your hot tub is 3-5ppm (parts per million) with 5ppm being the optimum reading

·        Bromine dissolves slower than chlorine but actively works for longer. Although you may have to use more in the first instance, you will not have to add it as frequently

·        Test the levels of bromine in your water using 6 in 1 testing strips

·        Can be purchased as bromine granules or bromine tablets

·        Bromine has a lower pH than chlorine so it can keep your hot tub chemicals more balanced and require less adjusting

·        Bromine is gentler on the sensitive skin, especially if you have sensitivities.

Choosing between chlorine or bromine as your hot tub sanitiser is now over to you. Remember irrespective of your choice, you’ll need to change your water and deep clean your hot tub every few months.

Whichever sanitiser you choose, you should test your water regularly to ensure the levels stay where they need to be to keep your water clean and keep you and your invited hot tub guests healthy and happy.

If you are unsure on which sanitiser would be the best choice for you to use in your hot tub, contact us today on 02921 280422 or WhatsApp on 07540184405.



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