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What is Pool Ozone? How It Works, Cost, Pros, and Cons

What is Pool Ozone? How It Works, Cost, Pros, and Cons

Pool Maintenance

If you think that ozone is a mysterious substance that only exists miles and miles up in the stratosphere, think again!

Ozone plays an important role in protecting us from the sun, but did you know that it can also protect you from harmful pathogens in your swimming pool?

Don’t worry, you won’t have to siphon ozone from the ozone layer in the sky to get it. In fact, you can make ozone right in your own backyard.

At River Pools, we specialize in manufacturing fiberglass swimming pools, and over the years, we’ve seen a wide range of pool sanitation methods. Ozone is one method that can be useful in both indoor and outdoor pools and spas, but is it right for you?

By the end of this article, you should have a better understanding of how pool ozone works, how much it costs, and some pros and cons of using it in your swimming pool or spa.


What is Pool Ozone?

Ozone is a blue-colored gas that’s made up of three oxygen atoms. Ozone is useful in swimming pools because it effectively kills and inactivates bacteria, parasites, and viruses. It's also a good oxidizer, which means that it can chemically destroy contaminants in the water. 

Rather than adding it to your pool the same way you add other pool chemicals, ozone sanitizes your pool water within the circulation system. Trust us when we say that you don’t want to come into contact with ozone gas while you’re swimming.

Once the circulated water is returned to the pool or spa, ozone is present at a very low and safe concentration, if at all. Because it does not maintain a residual disinfectant, another chemical, like chlorine or bromine, should be added to the pool to ensure that the water is completely sanitized and safe for swimming.

Ozone is unstable and untransportable, meaning you can’t buy it in tanks like you can with other gaseous chemicals. It must be generated on-site using an ozonator or ozone generator.

Let’s explain how an ozone generator works.


How Does a Pool Ozone Generator Work?

Ozonators, or ozone generators, are installed in the pool’s circulation system downstream from the operating equipment. As the water passes through the ozonator, it gets sanitized by the ozone before returning to the pool. Because ozone is not safe for humans, all or most of the ozone should be used up before the treated water is returned to the pool where it will come into contact with swimmers.

Keep in mind that your local or state health regulations may also require you to install an ozone detection system as an added precaution.

Another thing to keep in mind is the placement of your pool ozone generator. Any time you install and use an ozonator, it needs to have access to fresh air, and it cannot be underground.

Ozone is usually generated by one of two methods: corona discharge or ultraviolet light. Let’s briefly explain how these generators work.


Corona Discharge Ozonator

A corona discharge ozonator (also known as a corona discharge generator or CD ozone generator) uses high voltage electrical discharges to create ozone. It sounds complex, but the science is actually pretty simple: the electrical discharges create a ring of energy, and as air flows through that ring, some oxygen molecules get split apart and reassemble to form ozone.


How a pool ozone generator turns oxygen molecules into ozone


One thing to note is that it’s important for all moisture to be removed from the air before this process can take place. Your ozone generator will likely have an air dryer for this purpose. According to the National Swimming Pool Foundation, if the moisture isn’t removed first, nitric acid can form in the generator, which can interfere with ozone production and harm the equipment.


UV Ozonator

A UV ozone generator is a second method for producing ozone to disinfect your swimming pool. For ultraviolet light to turn air into ozone, air needs to be passed over UV lamps that emit light at 185 nanometers.

As the air passes over these lamps, the energy splits the oxygen molecules where they can then reassemble into ozone molecules. Remember, oxygen contains two oxygen atoms and ozone contains three. When the oxygen molecules split apart, they attempt to stabilize, forming ozone in the process.

Once the ozone is generated (using either type of generator), it needs to be dissolved into the water. The most common method is venturi injection. For this to take place, the structure of the device creates a pressure vacuum to draw the ozone gas into the pool water as it circulates through the system.


Corona Discharge vs UV Ozone Generators

Both types of ozone generators do the same thing in terms of scrambling the oxygen atoms to produce ozone. However, they differ in a few key ways. First, corona discharge generators produce a higher concentration and quality of ozone than UV generators. 

Keep in mind that CD generators are more expensive to buy and install, but they produce ozone at a cheaper rate.

Maintenance will also be different for each, so be sure to research each of your options before making your final decision. 


Ozone Pool System Cost

Pool Ozone Generator Cost

The price of a pool ozone generator can vary widely by brand, but one thing is pretty much always true: the more gallons of water that are in your swimming pool, the more you can expect to pay. This price can range from several hundred dollars to several thousand, with spa ozone generators being the most affordable.


Swimming Pool Ozone vs Chlorine

Although ozone and chlorine are both pool sanitizers, comparing them is kind of like comparing apples and oranges. Instead of pitting ozone and chlorine against each other, it might be a better idea to try using them together. In fact, they make a pretty good team.

If you use chlorine on an indoor pool, for example, an ozonator can offer another advantage to help you out in balancing your pool water chemistry. Ozone actually oxidizes inorganic and organic chloramines to help reduce combined chlorine, which can cause skin and eye irritation. This can go a long way in improving the air quality in indoor swimming pools.

Ozone also works well with bromine in pools and spas as a supplemental disinfectant and oxidizer. As you might remember from our article comparing bromine vs chlorine, bromine breaks down faster when exposed to sunlight or artificial UV light, but ozone won’t have this effect on bromine.


Ozone Pool System Pros and Cons

Now that you know how pool ozone systems work, let’s get into a final list of pros and cons to help you decide if it’s right for your swimming pool or spa:



  • Works with inground, above ground, indoor, and outdoor pools
  • Works with fiberglass, vinyl liner, and concrete pools
  • Multiple options (CD and UV generators)
  • Effectively kills and inactivates bacteria, viruses, and parasites



  • Ozone is dangerous for humans and needs to be carefully contained
  • Ozonators can be expensive to buy and install
  • Acts as a supplemental sanitizer and oxidizer only (you will need additional chemicals like chlorine or bromine)

What is your experience with swimming pool ozone? Leave your comments or any questions that you may have below. 


At River Pools, we manufacture fiberglass pools for customers across North America. If you're interested in a fiberglass swimming pool for your home, take a look at our catalog of models and see our fiberglass pool gallery for more ideas. 

Want to know how much your fiberglass pool might cost? Contact us today to request pricing, and in the meantime, try out our pool pricing calculator for a fast estimate:

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Want to see about how much that cost will be with all your favorite pool accessories?

Use our Design and Price Tool to walk through your options and approximate price!



If you're still looking for the right inground pool, be sure to download our free ebook below which takes an in-depth look at the three main inground pool types. 


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