What Is Cyanuric Acid or Chlorine Stabilizer?

Most pool owners add cyanuric acid to their swimming pool every year, but do they REALLY know what it is and what it does? It’s actually a pretty common chemical that only needs to be added once at the beginning of each season, or depending on your pool, sometimes not at all.

Cyanuric Acid, otherwise known as Chlorine Stabilizer or Conditioner, is what protects your chlorine from being eaten away by the sun’s ultraviolet rays. The sun can eat up to 1PPM (part per million) of chlorine every hour if it’s not protected.

Most chlorine that you find in tablet, stick or grandular form, have cyanuric acid as an ingredient, which is why you only need to add it at the beginning of the year,  “just to get a base.” After that, every time you add chlorine to your pool, you’ll be keeping your levels of cyanuric acid in check. Be sure to keep an eye on these readings throughout the year. You want to keep your cyanuric acid levels between 30 and 80 PPM in your pool at all times. I recommend keeping it around 40 PPM.

NERD ALERT!
Chlorine tablets, sticks and grandular are known as Cyanurates, which basically means they contain cynauric acid as an ingredient. Make sure, when you’re buying chlorine, to look out for chlorine tablets, sticks and grandular made with calicum hypochlorite. Calcium hypochlorite is the active ingredient in chlorine based shock and it does not contain cyanuric acid.

Testing For Cyanuric Acid

You can buy test strips that include cyanuric acid readings on them or you can buy a separate liquid test kit that has it. These are usually kind of expensive though. Since you really don’t have to keep a close eye on these readings, it’s best to just take a sample of your water to your local pool store that offers free water testing and just have them check it there every once in a while.

When Should You Add Cyanuric Acid?

Because most chlorine contains small amounts of cyanuric acid, you only have to add it about once at the beginning of the year to set it up. Once you have a good base of cyanuric acid in your pool, each time you add chlorine, it should keep it regulated throughout the year. However, if you have a to drain a large amount water out of your pool for any reason throughout the year, you may need to add more to bring your levels back to normal.

How To Add Cyanuric Acid

Cyanuric acid can be tricky to add to your swimming pool. Some chemical companies will tell you to dissolve it in a bucket of water. Keep in mind that Cyanuric acid dissovles very slowly. Other companies will tell you to add it directly to the pool. I would recommend dissolving it in a bucket of water, no matter what. Cyanuric acid is in fact, an ACID, so adding it to your liner pool and having those slow dissolving acidic grandulars sitting on your liner is not really a great idea.

NOTE: Whatever you decide, do not add cyanuric acid through the skimmer and through the filter. In fact, don’t add any chemicals that way!

Cyanuric acid is a very important chemical when it comes to good pool care. It allows you to maintain a healthy chlorine reading without constantly adding chlorine to your pool. Those hot summer days can really wreak havoc on your pool’s chlorine reading. Be sure to keep your levels in check this season.