What Chemicals Do: Cyanuric Acid, Ozone, UV light, and CO2

Our fourth and final installment of important pool chemicals will be focused on one chemical that only applies to certain pools, and a few alternative methods of achieving (and helping us achieve) our goals with chlorine and pH, much like the alkalinity and calcium hardness these are lesser known, but can be important to operating your pool at peak efficiency!

So let’s get right to it!

What is Cyanuric Acid?

Cyanuric Acid is a chemical that acts as a layer of sunscreen, not for the people in your pool of course, but for the chlorine in your pool. Which is why Cyanuric Acid is used exclusively at outdoor pools.

What is Ozone?

Ozone is a chemical that is used to aid chlorine in its responsibilities, and is used as a secondary form of disinfection and oxidation. While it cannot be used as a primary source of disinfection and oxidation, it is excellent at its job and serves as a secondary layer of protection.

What is UV Light?

UV light is the same type of light we are exposed to outdoors everyday, however it is more concentrated, and like Ozone, functions as a secondary form of disinfection and oxidation. Also like Ozone, it too cannot be used as a primary source.

What is CO2

CO2 or Carbon Dioxide is a common chemical found in the world; we all breathe it out, in fact! But in the pool setting, CO2 can be used alongside muriatic acid to manage your pH. As with Ozone, there are benefits to using CO2 systems alongside your primary chemical management systems, even though CO2 should not be used as your sole pH lowering chemical.

Why adjust Cyanuric Acid?

Chlorine is a powerful chemical, and arguably the most important in keeping your pool clean. However, chlorine, is vulnerable to UV from sunlight, which destroys any chlorine in your pool quickly. Without protection, your chlorine feed systems will be constantly running, costing you valuable money and other resources.

Cyanuric acid works as sunscreen for the chlorine in your pool, protecting it from being so easily destroyed by sunlight. With the right amount of Cyanuric Acid in your pool your chlorine will stick around long enough to properly do its job.

Why use Ozone?

Ozone, as we said before, can be used as a secondary source of disinfection and oxidation, but it cannot be used as your primary method. The reason for this is that unlike all the chemicals we’ve discussed up to this point, ozone doesn’t just remain in your pool water all the time, it’s much too dangerous for that! Instead it treats all the water it comes into contact with and remains separate from the rest of your pool water.

Why use UV Light?

Just like to Ozone, UV light cannot be used as a primary source of disinfection and oxidation in your pool because it can only perform those functions on the water it comes into contact with. So any water that passes through the UV light chamber is disinfected and oxidized immediately. However, it still only applies to the water that is passing through the chamber. So maintaining a chlorine residual is important in keeping your pool clean.

Why use CO2?

CO2 is best used when in conjunction with traditional acid feed methods. But, why use CO2 then, you may ask. And the reason is simple, because CO2, aside from lowering pH also has a secondary effect; it raises Alkalinity! If you read our last chemical post about alkalinity you will remember that alkalinity helps keep pH stable, so having a chemical that can help regulate its own stability is great!

Of course, if alkalinity is constantly being raised by CO2 it can make it difficult or near impossible to incite the changes you want to see to pH when necessary. Which is why it’s important to alternate between CO2 and a traditional muriatic acid feed, depending on your alkalinity level.

How dangerous are these chemicals?

Cyanuric Acid is, of course, an acid, so it should be handled with care. Unlike muriatic acid though, cyanuric acid is bound in granular/powder form. As an acid you should make sure you use a respirator, eye protection, and definitely wear gloves to keep your hands safe!

Ozone is a chemical that you should never have to come into contact with when in use at your facility. It is self contained and the equipment should only be serviced by trained professionals.

UV Light, while not a chemical, is self contained like Ozone, and the unit should only be serviced by a trained professional.

CO2 is a chemical that you won’t have to come into contact with or handle in any way!

Cyanuric Acid in Daily Operations

If you’re operating an outdoor pool you should keep a residual
of around 10-30 ppm in your pool. The lower you can get away with while maintaining a chlorine residual without feeding constantly, the better.
The reason for this is because cyanuric acid stabilizes and makes your chlorine ineffective. So if you have too much cyanuric acid, it can be just as problematic as having none.

You shouldn’t need to check cyanuric acid daily, but every week or two should be sufficient to maintain levels. The titration tests are ineffective at reading the levels of cyanuric acid that are ideal to keep in your pool, so using photometer is the only/best way to get an accurate reading.

Special Considerations for Ozone, and UV Light

While there are no ways to handle Ozone and UV Light it is important to note that both of these mechanisms don’t just destroy and disinfect the bacteria in your pool. Ozone is so strong it will destroy everything in the water, including your chlorine! And just as the sun will destroy unprotected chlorine, so too will UV light.

Finding the right balance of water passing through the systems is key to implementing them correctly, in order to see savings in your overall chemical usage. But this will be considered by whoever installs the systems.

For further information on the topics discussed in this post check the following locations:
Cyanuric Acid Ozone UV Light CO2

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Have any questions or experience with these chemicals? Let us know below! We’re happy to answer questions!