What water care options get you as close as possible to a chemical-free hot tub?

If you maintain an aquarium, koi pond, or even a bird bath at home, you know the difficulty of achieving chemical-free water care. It doesn't take very long for untreated water to develop a tell-tale layer of film and for the container it's sitting in to become coated with algae. Even untreated water that is constantly filtered becomes cloudy and needs to be changed often.

To prevent contamination of water in hot tubs, owners typically add a class of chemicals called halogens that include chlorine, bromine, and iodine. When mixed with water, halogens form weak acids that are very effective at killing bacteria and fighting viruses. They work as oxidizers that burn away organic compounds. However, these acids can also irritate the eyes and skin, which is why many people long for a chemical-free hot tub water care system.

While chlorine and bromine systems are the industry standards, a chemical-free hot tub depends on alternative treatments and creativity from the owner, at the very least. Even then, sanitizers must be introduced before you can safely immerse yourself in the spa water. So, a truly chemical-free hot tub is not altogether possible.

It is possible, however, to get closer to a chemical-free spa environment with a system innovative enough to generate its own cleaning power. Ozone systems take an important step in the direction of fewer chemicals. And breakthrough salt water hot tub systems are able to bring together crystal clear spa water with fewer chemicals.

How alternative water care systems bring you closer to a chemical-free hot tub

The idea of a chemical-free hot tub water care system points to greater convenience because there is no need to measure additives. The water care systems that get close to chemical free do the work of generating reactive molecules that kill bacteria in the process of becoming non-reactive molecules.

The most common system of this type is an ozone system. Ozone is a molecule that consists of three oxygen atoms instead of the usual two. This extra atom of oxygen leaves the ozone molecules unstable and very reactive with the organic compounds that make up microbes, as well as oils from skin and lotions.

When a molecule of ozone encounters one of these compounds, it breaks apart, forming regular oxygen molecules (O2). And that third, free oxygen atom binds with the foreign compound to make a new compound. Effectively, ozone rips microbes apart. It will also do the same with other compounds in spa water, allowing them to be more efficiently filtered out.

Because ozone systems tend to process chlorine too quickly, ionized silver is often used as an antimicrobial agent instead. In combination, an ozone system and silver ion purifier help to reduce the amount of chemicals you need in your spa. However, you will still need to add MPS, a non-chlorine oxidizing shock treatment every time before you use your spa. And it will still require a small amount of chlorine on a weekly basis to keep your water fresh and long lasting. While ozone systems can't claim to be entirely chemical free, they offer a great water care option and alternative to the traditional chlorine- and bromine-dependent systems.


If you search online for “chemical free hot tubs,” you may be surprised to find spa products as result—bottled additives that are sold as “natural” water care alternatives. These additives are enzymes, proteins that serve as catalysts for a chemical reaction. Calling them “chemical-free” hot tub treatments is a bit of a misnomer because, in reality, they fall under a specialized class of chemicals—albeit, ones that occur naturally.

In hot tubs, enzymes work by breaking apart the oils that are introduced into the water when bathers sweat or as suntan lotions wash off. Enzymes make it easier for the filters to remove the oils and helps to keep the water clear. However, they do not significantly reduce the levels of bacteria and other microbes present.

Although enzyme treatments can have a positive effect on water clarity and feel, they are not sanitizers. At best, enzymes act as supplements to water care, helping to keep hot tub water free from organic compounds. While non-halogen water additives can't combat microbes, you can find built-in water care systems that require almost no chemical additives and still significantly reduce bacteria numbers for a clean, stress-free soak.


If you're looking into chemical-free hot tubs then you're likely worried about the effects of chlorine and maybe—to a lesser extent—bromine. Unfortunately, there isn't a way to get rid of water-sanitizing chemicals completely and still have a spa you can enjoy without some concerns.

Using your hot tub without any sanitizers at all is unsafe, and adding them only when you're ready to use your spa is inconvenient. Plus, you can easily add too little or too much. Reducing chemical sanitizers instead of removing them completely is the safer choice. Today's more innovative salt water systems do just that—they reduce chlorine levels while keeping your hot tub safe and sanitary.

The new FreshWater® Salt System* from Hot Spring® is a factory-integrated, cartridge-based system that generates chlorine from salts. The chlorine is introduced into spa water at a steady rate over time, instead of all at once in a large amount. The chlorine effectively sanitizes your spa but is at a low enough level to be gentle on your skin, eyes, and hair.

The Freshwater® Salt System** is among the best salt water system for home spas. It's a low-maintenance and easy-to-use system because it works in-line with your spa's controls. Replacing the cartridge is simple and done directly from the spa's bar top. Also, because of the low, but effective, level of chlorine the system produces, spa water can last up to a year, helping to conserve water and save money. When combined with FreshWater® Mineral Spa Sanitizer, the system provides the ultimate in clean, silky, sanitary spa water.

Hot Spring is dedicated to providing reliable, easy-to-maintain hot tubs for our customers. To learn more about Hot Spring spas and the many benefits of the new FreshWater® Salt System, download a brochure.

*The FreshWater® Salt System cannot be used on Hot Spring® hot tubs manufactured prior to 2019.

**Factors such as bather load and water chemistry can impact water life. When the spa is properly maintained, a 3-pack of cartridges with the FreshWater Salt System will keep water clean and fresh for a full year. Product availability depends on your region. Please check with your local dealer.