Do You Need A Pool Ozone Generator? (Hint: It Depends)



You know the expression, “It’s not about what’s on the outside, but what’s on the inside that counts”?

Well, when it comes to swimming pools, this could not be more true. 

It doesn’t matter how beautiful and luxurious a pool looks. If what’s in it is on par with sewage water, no one’s gonna be using that pool.

There are various methods for keeping a pool sanitized, and a pool ozone generator is one that is starting to gain in popularity.

What Is Pool Ozone?

Not just a thin layer in the sky that protects us from UV rays, ozone (O3) is a blue-colored gas that’s composed of 3 oxygen atoms. 

When it comes to pools, ozone can be created to sanitize the water, removing harmful bacteria, debris, and viruses. Ozone oxidizes the water by adding oxygen to it, effectively killing off these pollutants.

Most commonly, chemicals such as chlorine or bromine are added to the pool to keep the water clean. Ozone isn’t added the same way because it can be harmful to humans in large doses.

Instead, pool ozone gas is added within the circulation system (pool pipes) rather than in the pool itself. This keeps the ozone levels low and safe for swimming when the water is returned to the pool.

However, as there is such a low level of ozone in the water (sometimes none at all), you’ll still need to use a sanitizer like chlorine or bromine to keep the water 100% clean.

Ozone vs Chlorine

Chlorine is the go-to sanitizer for most pool owners. With chlorine, you get a sanitizer and an oxidizer in the same chemical.

Chlorine comes in liquid, powder, or tablet forms, and fights off a range of pollutants that show up in your pool water: microorganisms, organic matter, debris, and algae.

Sanitization occurs because chlorine releases hypochlorous acid and hypochlorite ion known as free chlorine. When free chlorine is used up either through sanitizing, or being broken down by the sun’s UV rays, it becomes combined chlorine (also known as chloramines).

Chloramines are a harmful gas that has a very strong chlorine smell. They’re an irritant to humans, and can cause health problems if exposed to them for long periods of time.

Small amounts of ozone produces no such problems for humans, and the best approach to using it in your pool water is to actually pair it with chlorine.

The benefit of using this 2-sanitizer approach is that ozone is a much stronger oxidizer than chlorine (almost 100 times stronger!). 

This means that ozone systems can take care of the heavy lifting (cleaning all the pollutants in the water), freeing up the free chlorine to provide a “backup” cleaning effect in the water.

How Does a Pool Ozone Generator Work?

Oxidation is a process that happens in pools by either adding oxygen to the water, or adding a chemical that’s an oxidizer.

Pool ozone generators physically create O3 (three oxygen molecules) and release this gas into the pool water. Due to the fact that O3 is unstable, it looks for physical things to attach itself to – in this case, debris in the pool water.

When it attaches to the debris, it not only stabilizes itself, but simultaneously oxidizes the debris.

For health reasons, pool ozone generators have to be installed outdoors and in the pool’s circulation system, so it can “filter” the water safely.  Depending where you live, you may be required to have an ozone detection system installed with it.

There are two ways that ozone can be generated to oxidize pool water:

Corona Discharge

The term “corona discharge” refers to an electrical charge, and not a side effect of COVID-19, or the morning after heavily drinking a certain Mexican beer.

This charge breaks apart oxygen molecules in the air that pass through its chamber, creating ozone.  

The dielectric at the heart of this system has an electrical charge diffused over it, resulting in high concentration and quantities of ozone being produced.

Corona discharge can be set up in various strengths, tailoring it to the application it’s needed for and how much is required.

As they create a lot of electrical activity, it is important to keep them cool and well-ventilated at all times. 

Furthermore, this generator needs to remove all the moisture in the air before creating ozone. If it doesn’t, the result will be compromised ozone production and potential equipment failure. Most of these generators will include an air dryer specially for this purpose.

Corona discharge generators are initially more expensive, but create large amounts of high quality ozone at a cheaper rate.


UV, or ultraviolet, is another way to break apart oxygen molecules and create ozone. This method passes air over UV lights at a wavelength of around 185 nanometers. 

After the oxygen molecules are split, they reassemble into ozone. The ozone is then infused into the pool water through venturi injection – which uses a pressure vacuum to inject the gas into the water as it goes through the circulation system.

The Pros & Cons

So far, pool ozone generators sound like a pretty good solution to keeping your pool clean, and your chlorine consumption low.

Let’s take a closer look at the upsides and downsides to this option.


  • Works With All Pools: Whether you have an indoor pool, an outdoor pool, inground, semi inground, or above ground, a pool ozone generator will work with them all. This makes it easy to convert your existing pool without having to shell out for an entire backyard overhaul.
  • Multiple Options: This isn’t a one-generator-fits-all situation. You have various models you can choose from for small to large pools, and you can also decide for yourself if you want to use a corona discharge generator or a UV generator.
  • Reduced Chlorine Demand: Ozone will oxidize the majority of contaminants, leaving chlorine to do fairly little other than act as a consistent backup. This will save you spending tons of money on it. If you have a saltwater pool, you’ll also get extended life from your salt cell when using ozone.
  • Helps Keep Water Chemistry Balanced: Ozone wont change the water’s pH level, so you won’t have to re-balance the pool water’s chemical make-up as often. Goodbye weekly pool shocking!
  • Ozone Dissipates Quickly: Ozone quickly reverts back to oxygen once the water is passed through it. This is vital so you aren’t breathing in harmful ozone gas while swimming.
  • Safe For Pools: Ozone is pool friendly. It won’t eat away at the pool finish, and because it reverts back to oxygen quickly, there will be minimal to zero ozone actually entering the pool.


  • Needs To Be Well-Contained: Ozone is dangerous for human consumption, so it’s imperative that it’s well contained. This is why the generator is located far away down the filtration chain so the gas can’t enter the pool.
  • Still Needs Additional Sanitizers: It takes between 3 to 4 days to fully ozonate a pool. Even after it’s done its job, the pool needs an additional sanitizer (chlorine) to keep the water clean.
  • Only Works With Certain Pipes: You can only use ozone with pools that have PVC or stainless steel pipes. This is because it’s so highly reactive, that it will actually corrode most metals.
  • Can Become Expensive: The upfront cost of the generator isn’t too bad, and by using ozone you can save money on chlorine. But running the generator at all times is required, and that can result in a high electric bill.

How Much Does a Pool Ozone System Cost?

The price of a pool ozone generator ranges from $250 all the up to $1500. But on average, you should be paying between $350 and $700 for a residential-sized pool. Generally, the bigger the pool, the more expensive the generator.

Using an ozone system will help reduce chlorine and keep the pH level balanced for a longer period of time. From that standpoint, you may see a huge dropoff in the amount of money you’re spending monthly on chlorine and other pool chemicals.

However, where you’ll see a big spike is in your monthly electricity bill, as the generator has to run non-stop to keep the water filtered at all times.

Do You Really Need It?

Pool ozone generators are a great alternative to a chlorine or saltwater pool, but like anything, they do have their drawbacks.

However, if you’re looking to reduce your chlorine consumption, or don’t want to be exposed to so much of it all the time, an ozone generator can make a difference in the quality of your pool and health.

Categories: Pool Care, Pool Chemistry