How to Lower the Cyanuric Acid Level in Your Pool – Easy Guide

Cyanuric acid is also called a pool stabilizer, and it’s a very important ingredient in keeping your swimming pool both safe and comfortable. The cyanuric acid (CYA) number has to be just right to maintain and stabilize the chlorine levels in your pool.

If these levels aren’t well balanced it could burn your skin or your pool water may become cloudy because the combination of chemicals is off somehow. Fortunately, both testing and lowering the CYA level in your pool is easier than you think, and it doesn’t cost a lot, either.

lowering cyanuric acid in swimming pool

What Is Cyanuric Acid?

For the chlorine in your swimming pool to work properly, you need cyanuric acid, and it is usually added either by itself or dropped into the chlorine tablets so that both of these ingredients can be added at the same time.

The way CYA works is relatively simple. It bonds with the chlorine in your pool so that the chlorine isn’t broken down by the sun, making it much more effective on bacteria and algae. See my guide to using pool stabilizer here for more details about cyanuric acid.

Pool Mate 1-2607B Stabilizer and Conditioner for Swimming Pools, 7-Pound
  • Increases Cyanuric Acid Level
  • Decreases Chlorine Loss due to Sunlight
  • Reduce Chlorine Consumption up to 25%
  • Contains 100% Cyanuric Acid
  • Improves the effectiveness of chlorine

Although it weakens chlorine a bit to make it a little less abrasive, CYA won’t do anything to the pH level or alkaline level in your pool’s water, which means you don’t have to worry about it throwing off these numbers whenever you add cyanuric acid. It merely works with chlorine to stabilize and maintain the water in your swimming pool.

CYA is a must for people with outdoor pools because the sun can break down certain chemicals and make them ineffective. CYA prevents this from happening, and it also makes algae outbreaks much less common, in addition to allowing you to test your chlorine a lot less frequently.

Overall, cyanuric acid helps your chlorine work more efficiently and saves you both time and money year after year.

The Right Number Is Important

Just like any other ingredient you add to your swimming pool, cyanuric acid has to be the right number to be effective. The number you should shoot for is 30 to 50 ppm (parts per million), but even if you add a little less than this number, it will still do the pool some good.

Higher than 50 ppm, however, might prevent some of the bacteria from being killed, so try to stick as close to these numbers as possible for the best results.

Being a pool-owner means testing the water on a regular basis, and while you’re testing your chlorine and other levels, you should go ahead and test your CYA level as well. This can even be a fun task because the test strips they sell to test your cyanuric acid level are color-coded and eye-catching.

More importantly, they are super easy to read and therefore, you’ll always know exactly what number your cyanuric acid level is in your swimming pool.

Once you test the CYA level, it will either be just right, too high, or too low. If it’s too high, there are three things you can do to lower the number.

They include:

  • Wait for a heavy rainfall.
  • Buy yourself a cyanuric acid reducer.
  • Drain your pool and refill it with fresh water.

Dilution is the simplest way to get your CYA level back on track, and the good news is that it isn’t an exact science. If you test the cyanuric acid level and it is 10% higher than it should be, you can simply remove about 10% of the water in your swimming pool.

More often than not, this simple step will solve the problem and bring the CYA levels back to where they should be.

Cyanuric Acid Reducers

Of course, if your CYA levels are extremely high, purchasing a cyanuric acid reducer is likely the best solution for you. With this product, you can just follow the manufacturer’s instructions on the package to get the results you want.

With CYA numbers that are particularly high, a cyanuric acid reducer is much easier to use than the dilution method, because determining exactly how much water to remove from the pool can be difficult under these circumstances.

CYA reducers are simple to find because they can be found at most pool stores as well as online, and they’re very reasonably priced so you never have to let their cost determine whether or not to purchase this product.

Bio-Active Products Pool Stabilizer Reducer/Cyanuric Acid Reducer, 8 oz.
  • Reduces cyanuric acid levels by up to 50%
  • Eliminates chlorine-lock due to a high cyanuric acid level
  • Allows sanitizers to be more effective
  • Non-toxic, non-allergenic, non-polluting and leaves no residue
  • Ideal for draught stricken areas where a drain and refill are not possible

They are also easy to use and start to work immediately to get your cyanuric acid levels back to an optimum number.

One more thing: once you use the CYA reducer to lower the cyanuric acid level in your swimming pool, go ahead and top it off with a little bit of fresh water to improve the level even more.

Cyanuric Levels That Are Too Low?

For the most part, if you notice your cyanuric acid levels are too low – meaning below 30 ppm – it really isn’t much of a problem, but if you’re concerned about this, simply add some additional cyanuric acid granules per the manufacturer’s instructions and the CYA level should be just fine.

Clorox Pool&Spa 12004CLX Chlorine Stabilizer, 4 lb, 4lb
  • Helps chlorine last longer
  • Reduces sun's impact on chlorine
  • Perfect for salt pools, new pools and pools that use liquid chlorine
  • For best results, use with the Clorox Pool App
  • Power Source Type: Manual

In fact, even adding a handful of these granules can greatly improve the CYA level, but keep in mind that as a general rule, there is no need to be overly concerned with low CYA levels.

Cyanuric Acid Versus Muriatic Acid

Some pool-owners may be tempted to use muriatic acid in place of cyanuric acid, but this isn’t a good idea since the two chemicals serve two completely different purposes.

Muriatic acid is made to lower the pH level in the water of your swimming pool, while cyanuric acid acts much like a sunscreen for the chlorine in your pool. In addition, muriatic acid can be quite abrasive and even burn your skin and eyes if not added in the right amounts.

Did you know that muriatic acid is so strong it can be used to clean calcium scale deposits from your pool tiles?

Acid Blue Muriatic Acid - Swimming Pool pH Reducer Balancer
  • ✅ Vapor Reduction Technology reduces up to 90% of harmful vapors normally associated with 'old school' muriatic acid
  • ✅ Controls the pH level of water in pools - super effective pool water balancer
  • ✅ Brightens concrete & masonry surfaces
  • ✅ Removes stains from driveways or garage floors
  • ✅ Safer & Easier to use compared to standard muriatic acid

In other words, it’s always best to use each product for its intended purpose only if you want the best results.

In fact, this suggestion goes for anything you put into your pool, because it takes the right number of chemicals in the right combination to make and keep your swimming pool safe, comfortable, and swimmable day after day.

That being said, it is easy for some pool-owners to forget about the level of cyanuric acid in their water, but since it is so easy to test this level, it shouldn’t take you long to get into the habit of doing just that on a regular basis.

Now You Know How to Lower Cyanuric Acid!

Cyanuric acid works to make your chlorine much more efficient, and this saves you both a lot of time and also a lot of money. In fact, it has been proven that when you don’t use cyanuric acid on a regular basis, the chlorine in your water will kill bacteria three to five times slower than it would if you go ahead and use this chemical.

Bacteria left to multiply can create all sorts of pool water quality problems including green pool water and even pool foam in some cases! Find out how to fix those issues – or better still, prevent them in the first place!

Faster bacteria killing time means the water will stay fresher and safer much longer, which is what every pool owner wants.When you’re checking all of the important chemicals in your swimming pool, don’t forget to check the cyanuric acid level so that the chlorine does a much better job of killing bacteria and keeping your pool safe for you and your family.

Testing and adding CYA is a lot easier than you think, and the short amount of time it takes you to keep up with this level can save you both time and money from now on.

Last update on 2021-07-24 / Affiliate links / Images from Amazon Product Advertising API

michael keenan author

Author - Michael Keenan

I'm Michael Keenan the owner and creator of the Outdoor Care Guide. I'm a trained horticulturist with over 30 years experience in pool care, plant care and landscape care! Seemed like a good idea to share - I think I can make your life easier and save you some time and money!