Can You Use a Hot Tub Without Chemicals?

The thought of bathing in chemicals sounds pretty unpleasant, not to mention uncomfortable. So is there a way to use a hot tub without them?

It’s not possible to use a hot tub safely without chemicals. You can reduce or replace chlorine with alternative sanitizers such as saltwater systems, mineral purifiers, and ozonators. However, chemicals are still required to balance the pH and alkalinity levels. Insulated covers and blankets help reduce chemical use.

Running a hot tub without chemicals can quickly become confusing, so I’m going to explain how to do so as simply as possible, with extra information on:

  • Clearing up confusion surrounding chlorine and its safety
  • Natural sanitizing alternatives to reduce chemicals
  • Simple practises to minimize chemical use

What happens if you don’t put chemicals in a hot tub?

Hot tub chemicals are necessary to protect your spa, your health, and to enhance your bathing experience.

Using a hot tub without sanitizing chemicals may pose a safety risk in just a matter of hours by exposing you to nasty bacteria, viruses, and fungi such as E. Coli, Pseudomonas aeruginosa, and legionella. A build-up of bacteria in the water will also damage the spa and its components if left untreated.

Chemicals get an increasingly bad wrap as the world tries to move toward more natural and organic alternatives.

However, in the case of something like a hot tub, chemicals are absolutely unavoidable for keeping the water clean, clear, and free of contamination.

Certain bacteria and fungi thrive at temperatures between 80 and 104°F (27 – 40°C), which is the exact temperature range of your hot tub.

Hot tub folliculitis is a nasty skin infection that is caused by the bacteria Pseudomonas aeruginosa, which thrives in warm, wet areas like your spa.

The legionella bacterium causes Legionnaires’ disease, a severe form of pneumonia (lung infection), which can be potentially fatal.

Contact with people that have become infected can lead to fungal and bacterial infections, including the herpes virus.

In order to stunt their growth, powerful sanitizing chemicals like chlorine are necessary to treat the water. While bathing in chlorine sounds uncomfortable, it’s essential for making the water safe and pure.

Is chlorine safe?

When people seek alternatives to hot tub chemicals, what they really want is a more gentle alternative to chlorine. Chlorine can be harsh for those with sensitive skin and some may even have an allergy to this powerful disinfectant.

Allergies to chlorine are not all that common, however, so it’s best to make an appointment with your doctor to confirm your suspicions if you think it’s making you sick.

For most people, chlorine is perfectly safe. It’s the most widely used disinfectant in the world and is even used to treat drinking water in countries such as the US, Canada, the UK, and many others around the world.

If you’ve had a bad experience at a public pool, then it may well have been caused by a pH imbalance or perhaps, ironically, by a lack of chlorine.

I’m sure you’ll be pleasantly surprised to learn that the obnoxious odor we associate with chlorine isn’t caused by someone adding too much. It’s actually the opposite.

The smell is caused by volatile substances known as chloramines. Chloramines form in spa water when chlorine reacts with contaminants such as sweat, oils, urine, and skin cells are introduced to the tub by bathers.

With too much exposure, chloramines cause irritation to the eyes, nose, and throat, as well as contributing to respiratory problems.

By shocking your hot tub with extra chlorine once a week, you reduce the level of chloramines, which causes the smell and water quality to improve.

Chlorine is the number one choice for spas and pools around the world because it’s cheap, powerful, and fast-reacting. But there are many alternatives to chlorine on the market, some chemical and some natural. Let’s take a look.

Chemical alternative to chlorine

Bromine is an excellent chemical alternative to chlorine. Although it’s a bit more expensive, it’s the only chlorine alternative that doesn’t require the purchase of additional equipment.

While it’s not as fast reacting as chlorine, it’s gentler on your skin and far more stable at high temperatures. While chlorine is great for swimming pools, the higher temperatures found in hot tubs make bromine a better choice.

Unlike chlorine, bromine is able to regenerate when you shock the water. The fact that it does so means you don’t need to use it as much, making bromine a simple way to reduce the number of sanitizing chemicals you use to treat your water.

The fact that it regenerates means you also recoup some of the extra money you had to spend when purchasing bromine instead of chlorine.

Natural alternatives to reduce hot tub chemicals

If you really don’t like the idea of using chlorine or bromine, then the good news is that there are several systems on the market that dramatically reduce the number of chemicals needed to run a hot tub safely.

Mineral purifiers

Mineral purifier sticks create lasting protection as the system inhibits the growth of bacteria. The Nature2 Spa Mineral StickOpens in a new tab. is my absolute favorite, and I’ll show you why.

Installing a mineral purifier couldn’t be easier. It’s as simple as dropping the stick into the hole in the middle of your cartridge filter.

Mineral sticks are filled with silver and copper pellets that dissolve slowly into the water. Together they work as a biocide to keep your hot tub sparkling clean.

The silver oxide acts as the sanitizer and the copper acts as the algaecide. Using a mineral purifier will enable you to reduce the use of chlorine or bromine by up to 50%.

But 50% isn’t enough if you want your hot tub to be completely free of chemicals, which is why you need to pair it with CenseOpens in a new tab.. The Nature2 Spa mineral stick becomes a complete sanitizing system when used in combination with Cense.

Combining Nature2 with Cense creates the only non-chlorine spa sanitizing system available on the market.

Cense contains Potassium peroxymonosulfate, which works as a powerful non-chlorine oxidizer. It also has the added benefit of aromatherapy, being available in 4 different fragrances.

Saltwater system

Any tub can be turned into a saltwater hot tub with the addition of a saltwater system. Instead of adding chemicals such as chlorine or bromine, you add salt.

The salt dissolves in the water to produce natural chlorine that keeps your spa sanitized. It’s the process of electrolyzing the salt that generates this natural chlorine.

It typically costs between $500 – $5,000 to add a salt-chlorine generator system to your existing hot tub. Some of the benefits of a saltwater spa include:

  • More natural-feeling water that is softer and gentler on skin and doesn’t cause irritation to eyes.
  • The minerals in the salt making it more resistant to water chemistry fluctuations as it’s better able to withstand changes in pH, alkalinity, and calcium hardness.
  • No harsh odors and fewer chemicals are needed as the water stays balanced for longer.

Ultraviolet system

Another alternative is to use an ultraviolet (UV) system that sanitizes your hot tub by irradiating the water as it passes by UV bulbs.

Exposing waterborne pathogens to UV light of a specific wavelength within the UV-C spectrum for just a millisecond rearranges their DNA, rendering them unable to reproduce.

The fact that it’s a physical process rather than chemical makes UV disinfection the most environmentally friendly choice in hot tub sanitation.

The technology is increasing in popularity as it’s easy to use and has several benefits over harsh chemicals such as chlorine and bromine.

For starters, UV-treated water is gentler on your skin and eyes and causes less damage to your hair. It also improves water and air quality, which is especially important for those with indoor spas.


Ozonators, or ozone generators, sanitize hot tub water by shooting a small electrical charge to separate the two atoms in oxygen (O2) into single atoms (O).

Because the singular oxygen atoms become unstable, they bond to close-by O2 molecules in the air, forming O3, or Ozone.

Unfortunately, ozonators don’t eliminate the use of sanitizing chemicals such as chlorine or bromine; however, they will reduce their need by as much as 50%.

There are two types of ozonators on the market, and your personal circumstance will determine which one you need. Check out my comprehensive guide to ozonators to see if they are the right choice for you.

How to reduce chemical use with simple practises

There are several practices that you can easily implement to reduce the number of chemicals you need to run your hot tub.

Cover with an insulated cover and floating thermal blanket

Combining an insulated cover with a floating thermal blanketOpens in a new tab. is the best way to reduce the use of sanitizing chemicals.

Using a cover and blanket reduces evaporation by up to 95%, so you lose fewer chemicals to the air.

They also protect from dirt and debris that throw off the water chemistry, meaning you won’t have to use extra chemicals to balance the water.

Shower before use

The main reason that you’re hot tub water needs to be constantly maintained is due to the natural oils, bacteria, and personal care products that cause it to become unbalanced.

Taking a shower or simply rinsing off quickly is a simple and effective way to limit the number of chemicals you have to use to keep the water in check.

If you’re using personal care products such as makeup, hairspray, gel, perfumes, or sun cream, then it’s a good idea to shower thoroughly with soap and water before getting in.

Washing your swimwear by hand using hot water is another effective way to reduce the use of chemicals.

This is because the laundry detergent used when you wash in the washing machine plays havoc with your spa’s water chemistry.

Frequently test and adjust water chemistry

Regardless of how you choose to sanitize your hot tub, it’s vital to keep the alkalinity, pH, and water hardness within their recommended ranges.

The reason for this being that sanitizers are less effective when everything is out of balance.

Bacteria rapidly builds up in an unsanitized hot tub, which can cause you to become ill. The build-up may even damage your hot tub and components if left untreated for long enough.

Maintain your filters

It’s essential to perform a regular cleaning routine in order to reduce the number of chemicals that are needed to keep the water clean and healthy.

I’ve written an entire guide on hot tub filter care, which I encourage you to check out as there are many other benefits besides cleanliness, such as saving money on your energy bill.

You need to rinse the filters at least once per week, carrying out more thorough rinses monthly and deep cleans quarterly.

The filters must be replaced annually or when it’s no longer possible to get them clean using special filter cleaning products, whichever comes first.

Run your pump for longer

The reason your hot tub pumps need to run while not in use is to circulate the water to prevent it from becoming stagnant and a breeding ground for bacteria.

Every model varies slightly, but you need to run the pump at least 8 hours per day. Doing so will reduce the number of chemicals required to keep the water clean.

A simple way to reduce the cost of running your pump is to have it run during off-peak hours if this is included by your energy provider.

Drain your water frequently

As a minimum, you should be performing a complete drain of your hot tub every 3 – 4 months, and more if you’re a frequent user.

Check out the guide I created so you can calculate exactly how often you need to drain your spa.

The time comes when the water eventually becomes resistant to the chemicals you add, causes spa owners to add chemicals in greater quantities in an attempt to balance the water.

Performing a full drain enables you to start over again with fresh water. It also enables you to clean the hot tub shell and plumbing.

Partial drains are also a good idea if the hot tub has seen a lot of action in a short amount of time, perhaps because of a party or other social gathering.

Each time before you drain your spa water, it’s a good idea to use this Ahh-Some line flushOpens in a new tab. to get rid of any biofilm that’s likely lurking in the plumbing. Removing any traces of biofilm ensures that the fresh, clean water you add doesn’t become contaminated after refilling.

Joshua Milton

Joshua Milton is a seasoned hot tub enthusiast. With many years of experience in the industry, he offers valuable insights on hot tub maintenance, health benefits, and relaxation techniques.

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