Alternative Hot Tub Sanitizers That Really Work

Michael Keenan


Hot Tub Water Chemistry

Sanitizing your hot tub is a must if you wish to keep it both safe and comfortable, but if you dislike the combination of chlorine and bromine for one reason or another, the good news is that you do have alternatives. Let’s take a look at some alternative hot tub sanitizers.

Let’s face it, if you don’t like chlorine and bromine and you can’t find an alternative to this type of sanitizer, the only choice you have is to never soak in your hot tub again or soak in dirty water, and neither of these is acceptable to most people.

There are alternative hot tub chemicals you can use.

alternative hot tub sanitizers

Quick Answer:

There are some alternatives to chlorine and bromine hot tub sanitizers that can really help people with sensitivity to these chemicals. These include Biguanide, ionizers, Ozonators, and using Ultraviolet (UV) Light.

Just remember that these are secondary sanitizers and usually require the use of small amounts of either chlorine or bromine.

Why Switch to an Alternative Hot Tub Sanitizer?

Most people start off with chlorine and bromine sanitizers. They are relatively cheap and effective hot tub chemicals, but for some they cause problems.

Many spa owners don’t realize there are alternatives when it comes to sanitizing their spa. They just put up with the “side effects” of their current sanitizer and hope for the best. But if you experience any of the following, it might be time to look into using an alternative hot tub chemical mix:

  • A strong chemical smell either consistently or even occasionally.
  • Red, irritated eyes that burn and are uncomfortable.
  • Red, itchy skin or rash. It’s rare to be allergic to chlorine, but sensitivity to chlorine is not at all uncommon.
  • A “bleach” effect. If you have blond hair, it may start to turn green, and you may suffer with other things that are similar to suffering the effects of using bleach, including very dry hair and skin and a swimsuit that starts to fade.

All of these things are likely indications that the chlorine and bromine you’re using may not be agreeing with you, so it’s good to know that there are, in fact, alternatives to using these two chemicals. Some of these are listed below.

What are your Hot Tub Sanitizer Options – Alternatives to Chlorine?


Using a Biguanide sanitizer has become very popular with users wanting to avoid chlorine and bromine. It is much easier on the skin and eyes and still has great cleaning qualities.

The scientific names for biguanide include polyhexamethylene biguanide, polyaminopropyl biguanide, and polyhexanide. Nowadays, it is known simply by biguanide or even PHMB. Biguanide is a very efficient sanitizer for hot tubs and spas while being very gentle on your skin and eyes.

Some products on the market today include PHMB in them, including many brands of contact lens solutions. It is often sold under the name of BaquaSpa, or Baquacil for swimming pools.

Baquacil Sanitizer

Chlorine free pool and hot tub sanitizer that works a treat

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When using biguanide, you still have to shock the hot tub or spa, but you never want to do this with a chlorine-based shock. Instead, you have to use a non-chlorine or a non-bromine-based shock to get the best effects. Indeed, this is an excellent sanitizer for your spa that is both easy to find and reasonably priced.

Baqua Spa Sanitizer

Baqua Spa Sanitizer Chlorine-Free Cleaner for Spas and Hot Tubs

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Ionizers combine both copper and silver because both have strong antibacterial properties. They are often called mineral sanitizers.

In fact, the antibacterial properties of silver have been known and used since the ancient Roman times, so it’s a remedy people have been aware of for a very long time.

An ionizer sanitizer for spas works by releasing silver and copper ions into the water, which in turn will kill bacteria and any other contaminants you might have in your water.

Unlike UV sanitizers, however, they do not prevent your water from becoming cloudy.

In addition, ionizers do not work on their own but instead, they need to be supplemented with either chlorine or bromine so that your spa is completely sanitized.

You won’t need a lot of chlorine or bromine, but you will have to use some to make your ionizer work the way it’s supposed to work. Maybe not ideal if you have a severe reaction to chlorine.

Hot Spring Spas Freshwater Ag+ Continuous Silver Ion Sanitizer

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If you’re interested in a more natural way to sanitize your spa, you might want to consider using an Ozonator. Used without any chemicals, hot tub ozonators come in numerous sizes to accommodate all types of spas, and they work by injecting ozone into the water to sanitize it.

These devices are usually a bit more expensive than many other types of spa sanitizers, but they can also be looked at as an investment in your hot tub.

You may have to modify your hot tub to accommodate an Ozonator, but if your goal is to operate and use your spa with fewer chemicals, this option is worth considering.

DEL Ozone Hot Tub and Spa Eclipse Corona Discharge Ozone Generator

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DEL Ozone Hot Tub and Spa Ozone Generator

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Ultraviolet (UV) Light

Most people know that sunlight can kill bacteria, and the reason is because of the ultraviolet rays emitted from the sun. This is why there are now UV sanitizers that help clean and sanitize your cell phone, keys, jewelry and many other items that may be hard to clean otherwise.

Now, you can also purchase hot tub sanitizers that utilize this same power so that bacteria and other contaminants in your spa water can be eliminated. Using low-grade radiation, the UV hot tub sanitizers do a great job at this every time.

That being said, UV sanitizers for spas will not keep the water clear and therefore, you’ll still need to shock your hot tub on a regular basis. In fact, chlorine and bromine might still be necessary to keep the water both fully sanitized and clear. See my guide on how often you should shock your spa.

If you decide to use a UV light sanitizer for your spa, keep in mind that you might still need a traditional sanitizer, although you likely won’t have to use nearly as much.

Primary Versus Secondary Spa Sanitizers

You may have noticed that these alternative spa sanitizers often have to be used along with other sanitizers, including small amounts of chlorine and bromine. This is because they are secondary and not primary sanitizers.

Primary sanitizers, which include chlorine and bromine, can be used by themselves and need no other chemicals or products to make them work properly. On the other hand, secondary sanitizers need something else to work properly.

Are There Other Types of Sanitizers?

Salt water sanitizers for spas are another alternative to chlorine and bromine, but again, these are secondary sanitizers and therefore will likely need at least small amounts of chlorine and bromine added to them.

Like ionizers and ozonators, salt water sanitizers use a natural chemical reaction to kill all of the bacteria and contaminants in your spa’s water, and in the case of salt water sanitizers, that process is called electrolysis.

The way it works is simple. You simply add salt to your hot tub’s water. The chlorinator cell, or salt cell, in the sanitizer, reacts with the salty water in the hot tub and then produces chlorine gas.

It is this chlorine gas that works to kill the bacteria and contaminants in your spa water, and it does so without the irritation usually associated with regular chlorine.

Saltwater sanitizers are just like the other alternative types of sanitizers in that they won’t work by themselves yet they at least reduce the amount of chlorine and bromine that you need to put in the water so that you can have fewer chemicals in your spa overall.


If you don’t enjoy the side effects of the chlorine and bromine that you are required to put in your hot tub or spa, it’s good to know there are alternatives to sanitizing your spa’s water so that you don’t have to use as much of these two chemicals if you don’t want to.

Remember, if you want to switch to an alternative sanitizer you’ll need to start from scratch. It is a good idea to completely drain and clean the hot tub to remove all traces of your old chemicals.

Then refill and add your new sanitizer set up. And remember to test your hot tub water regularly to get things just right. Used properly, and with good hygiene practices, alternative sanitizers should help prevent problems like white mold in your hot tub.

These alternative hot tub sanitizers offer the same positive effects as chlorine and bromine do but can help people who are extra-sensitive to these two chemicals’ effects on the body.

michael keenan author

Author - Michael Keenan

I'm Michael Keenan the owner and creator of the Outdoor Care Guide. I'm a trained horticulturist with over 30 years of experience in pool care, plant care, and landscape care! Seemed like a good idea to share - I think I can make your life easier and save you some time and money!