Written by 11:40 am Chemistry

What is Pool Ozone?

Crystal Clear Pool Water

The maintenance needs for a swimming pool can sometimes feel out-of-this-world. Is there a way to bring them back down to earth?

More and more pool owners are turning to pool ozone systems. These devices use naturally occurring gas to help remove contaminants from the water, resulting in a clean, sanitized pool and less need for chlorine.  

If you’re considering a pool ozone system, here’s a deeper dive into what it is, how it works, and much more.

Pool Ozone Defined

Let’s start with a bit of science – don’t worry, we’ll keep it simple.

Ozone (O3) is a blue, inorganic, and unstable gas made from three oxygen atoms. It forms when a free oxygen atom collides with an oxygen molecule (O2). In nature, this formation occurs in two ways:

  • During a lightning strike
  • Through ultraviolet radiation

Ozone can also be manufactured, which is how pool ozone systems work. There are two methods used to make ozone: corona discharge and ultraviolet light (we’ll explain each further down).

How Does Ozone Clean a Pool?

Ozone is what’s called an oxidizer, which means it removes electrons from certain chemicals. The oxygen atoms collide in a pool and then destroy foreign contaminants, such as algae, bacteria, viruses, parasites, and oils.

Additionally, ozone is notable for what it doesn’t do. Because it’s gas, it has no effects on the pool’s pH levels.

How a Pool Ozone System Works

The main component of the system is an ozonator, which produces ozone. Because ozone is an unstable gas, storage is dangerous, so it must be made on-site.

After the ozone is produced, it’s pushed through the pool’s circulation system, where it disperses through the water and returns to the ozonator in a much lighter concentration. Large quantities of ozone aren’t safe for humans, so the process of making and dispersing the ozone happens quickly.

The most common way ozone dissolves into the water is via a method called venturi injection. Pressurized water creates a vacuum that pulls the ozone into the pool water. It then circulates through the entire system to reach all contaminants.

As mentioned above, there are two types of ozone generators:

Corona Discharge

Corona discharge ozonators produce a high-voltage electrical discharge. The resulting ring of energy splits oxygen (O2) molecules into single atoms. After forming, these single atoms quickly reattach to oxygen molecules in the air, creating ozone (O3).

Ultraviolet Light

UV lamps that have the capability to emit light at 185 nanometers can also split oxygen molecules, following the same process as above. The single molecules will reattach to oxygen in the air, making ozone. Aside from use in pools, certain types of UV lamps are used to clean and disinfect surfaces.

Ozone Pool Systems: How Much Do They Cost?

Generally, most ozone pool systems range in price from $1,000 to $3,000. Common factors that affect costs include:

  • The size of the pool
  • The system’s ozone output
  • The type and power of the generator
  • Whether the generator uses dry air or a separate unit to produce oxygen

The larger the pool, the larger and more expensive the ozone system needed to keep it clean. However, pool owners need to consider long-term maintenance costs. An ozone system reduces the amount of chlorine required to keep the pool clean, reducing wear and tear and lowering annual maintenance costs.


Aside from systems that only create ozone, you can also install a hybrid system, which combines an ozonator with salt and chlorination. While hybrids are generally more expensive than ozonation-only units, you can ultimately save on maintenance costs by having all pool sanitization housed within a single system.

Ozone Generator vs. Chlorine Treatments

It’s important to note that ozone pool systems don’t create residual disinfection. The only time the system destroys contaminants is when it’s running. So, you can’t use ozone as the sole sanitization method for a pool. Instead, you will have to use ozone alongside chlorine.

Chlorine in liquid or tablet form is a standard method of killing bacteria and other harmful contaminants in drinking and pool water. Here’s a closer look at the benefits and potential drawbacks of both chlorine and ozone.

Pros of Chlorine

Chlorine is popular for a reason. Here are its key benefits:

Effective and Reliable

When chlorine comes into contact with water, it releases various chemicals, including hypochlorous acid (HOCI) and hypochlorite ion (OCI). They both kill all sorts of bacteria and microorganisms.

The effectiveness of HOCI and OCI heavily depends on maintaining the proper pH level in the pool. For example, if the pH is too high, the presence of HOCI is impaired, lengthening the sanitization process. The ideal pH level for most chlorinated pools is between seven and eight.

Affordable and Predictable Costs

Ozone systems don’t require any extensive upfront costs. Plus, because your pool doesn’t change in size, you likely won’t need to make significant adjustments to the amount of chlorine you use. Generally, you’ll need to use one chlorine tablet for every 5,000 gallons of water.

Safe for People, Pets, and the Environment

When used in appropriate amounts, chlorine is safe for human exposure. Of course, the key concept here is appropriate amounts, as swallowing chlorine or getting too much in your eyes can result in health problems.

Additionally, chlorinated water is unlikely to stain, bleach, or otherwise damage clothing, towels, wood, furniture, and other objects commonly found around the pool.

Cons of Chlorine

As pool owners know, chlorine isn’t without its issues, which is why many people choose to augment their chlorine sanitization with ozone. Here are chlorine’s main drawbacks:

Extensive Maintenance Needs

As described above, chlorine is most effective when the pH levels in the pool are adequately maintained. Unfortunately, keeping your pool at the correct pH level is often time-consuming and complicated. You’ll regularly need to test the pool and make adjustments as necessary.  

Potential Dangers

Pure, undiluted chlorine is potentially toxic. When handling it, you’ll need to take care not to get it on your skin or breath in any fumes. Considering how often you need to adjust chlorine levels, accidental exposure is always a potential risk.

Symptoms of chlorine poisoning include irritated eyes, dry skin, and difficulty breathing. 

Powerful Smell

Everyone’s familiar with that “swimming pool smell.” It’s the result of chlorine interacting with the bacteria in the water – and it’s hard to escape. The chlorine aroma sticks to skin, hair, and clothes even when a pool is properly maintained.

Pros of Ozone

Why do so many pool owners install ozone systems? The most common benefits include:

Reduced Maintenance

Ozone can drastically reduce the amount of time you need to spend keeping your pool clean. The ozone process is entirely automated. Plus, ozone treatments mean you have to use less chlorine.  

Reduced Odor

Because an ozone system lets you use less chlorine, your pool will give off less of a chlorine smell. Also, ozone helps mask the chlorine smell, leaving behind a light, fresh odor instead.

Another way ozone helps your pool area smell nice is by killing mold and mildew.

Best for Hard Water

Does your community use hard water, a type of water with high amounts of magnesium and calcium? Ozone treatments are your best option to prevent build-up. The oxidation process removes calcium carbonate and other minerals.

Cons of Ozone

Ozone generation systems do have a few drawbacks to watch out for. The main potential disadvantages include:

Not Suitable For Solo Use

Except for some extremely high-end systems, most pool ozone generators are meant to supplement existing chlorine treatments. While they significantly reduce the adverse effects of chlorine, you can’t eliminate chlorine from your pool completely. 

Initial Expense

Installing the ozone system will likely cost several thousand dollars. Plus, the price can vary depending on whether you place the system above ground or underground — and the location is determined by the specific layout of your pool and surrounding area, not your personal preference. 

Potentially Hazardous

Ozone exposure can potentially result in many painful and debilitating lung issues. While the gas is safe when adequately contained within the pool’s circulation system, you’ll need to ensure it never leaks. Also, watch out for build-up in small areas, such as within a pump room.  


A pool ozone system adds substantial sanitization benefits along with a notable reduction in maintenance needs and chlorine use. While adding a system does require upfront expenses, many pool owners feel the purchase is worthwhile and helps save money over time.

If you’re tired of all the effort required to keep your pool clean, consider the power of oxidation.

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