Using Pool Stabilizer (Cyanuric Acid) – the Easy Guide

Michael Keenan


Pool Water Chemistry

I’m going to help you get to grips with using pool stabilizer or cyanuric acid like a pro! I’ll cover everything you need to know and explain how to get the best results and have perfect pool water.

Most of us are die-hard fans of the shampoo-plus-conditioner combo and with good reason – conditioner possesses, among its many qualities, the ability to keep hair shielded from the damaging effects of the sun. Well, it turns out that your hair isn’t the only thing that may benefit from conditioning – your pool can too!

Pool conditioning, more commonly known as pool stabilizing, stabilizes the chlorine levels in your pool, keeping your water cleaner for longer. If you’re new to the world of pool maintenance, don’t fret – here’s all you need to know about the process!

using pool stabilizer cyanuric acid

What Is Pool Stabilizing?

Also called chlorine stabilizer, pool stabilizer or pool conditioner, scientifically known as cyanuric acid (CYA), keeps the chlorine levels stable in your pool, extending the chemical’s sanitization strength for longer.

Why Is This Necessary?

Chlorine, as you probably already know, is an extremely important chemical in the pool, keeping the water clean and safe for swimming. It does this by preventing algal growth and killing/neutralizing/attacking any harmful bacteria and microorganisms.

Well, turns out, the sun can consume up to 90% of the free, unstabilized chlorine in your pool. No, not over a week or two – more like in an hour or two! Therefore, a buffer is required to protect your protector.

Cyanuric acid efficiently accomplishes this job, acting as a buffer and protecting the chlorine from the sun’s notorious UV rays. CYA is available in either granular or liquid form, as well as in the form of chlorine sticks (trichlor), chlorine tablets and chlorine shock (dichlor).

Though most chlorine products you’re probably using to keep your pool clean already contain CYA, adding a dose of CYA once, at the beginning of the swim season, ensures that your pool is sufficiently stabilized.

Some pool chemicals such as sodium hypochlorite and calcium hypochlorite shock Must be used with a stabilizer like CYA.

Are you using an automatic pool chlorinator? Find out why you should in that article!

If you paid attention so far, you’ve probably picked up the bit about sunlight eating up your chlorine. So does this mean that indoor pools and covered pools don’t need CYA?

Yes, indoor pools don’t need CYA. Pools that are not exposed to sunlight do a pretty good job of maintaining and balancing their levels of chlorine.

So How Much Stabilizer Is the Right Amount?

Though opinions differ on the subject, a good amount is to keep your stabilizer between 30 and 50 ppm. Anything below 30 is too low and anything above 50 is too high.

Some experts even suggest 80 ppm, but this is a minority population and generally, levels above 50 ppm cause chlorine lock, which is a phenomenon where your chlorine tests will read negative despite there being some in the pool!

Even if you’re sticking to an amount between 30 and 50 ppm, ensure that you’re constantly monitoring the available chlorine levels in the pool, with the added stabilizer. This means you’ll have to consistently test the water, but hey, no pain, no gain!

Another great rule of thumb is to keep the sanitizer levels to approximately 7.5% of the stabilizer amount. This means, for 50 ppm of stabilizer, you’ll have a pool with 3-4 ppm of free chlorine levels.

Therefore, for every 10,000 gallons of water, you can use about 4 lb of CYA and raise this amount for every 30 ppm.

If you don’t really love doing the math, don’t worry – when in doubt, always refer to the product instructions listed on the label and your proper dosage queries are sorted. There are also several handy calculators online that can do the dirty work for you!

How to Add Stabilizer to the Pool

Most CYA packages recommend that you add CYA to the pool after mixing it into warm water in a bucket, whereas some others say you can directly pour it into the pool. So what method do you use?

Dissolving / diluting chemicals before adding to them anything is a good idea. Doing so will also prevent any possible skin irritation or damage to the pool liner. It also ensures an even mix in the water.

Why Does Stabilizer Need Balancing?

Though CYA protects your chlorine, too much of anything is too bad – the same remains true for CYA too.

If CYA levels are too low in your pool, your chlorine will be eaten up by the sun, as mentioned earlier, in a matter of hours. When this happens, your swimming pool becomes a breeding ground for algae and bacteria.

However, if the stabilizer level exceeds the recommended balance level, it can turn out to be counterproductive – the stabilizer will overpower the chlorine and render it less effective. Extremely excessive amounts of stabilizer can also lead to chlorine locking.

Excessive Stabilizer Levels

Sadly, CYA levels don’t reduce on their own, even with time. If the CYA levels in your pool are too high, many folks swear by a product called a CYA reducer. However, whether or not this actually works is yet to be proven and a lot of debating still surrounds the product.

However, if this is something you’d like to try, try a product such as the Bio-Active Products Pool Stabilizer Reducer that can reduce CYA levels by 50% and prevents chlorine lock.

Find out how to how to lower the cyanuric acid level in your pool in this detailed guide.

However, the most foolproof way to keep the stabilizer levels balanced is to dilute it, which means that you’ll need to add some fresh water to a portion of your pool water that you drain.

Low Stabilizer Levels

Sometimes, though you’ve already added CYA to the pool at the beginning of the swim season, you may have to add it again, when the pool water has reduced (such as through pool parties) or if it has been diluted in any way since you first added CYA (such as rainfall).

Once you’ve tested the CYA levels and find that they’re too low, calculate the amount of CYA you would need to bring the level back to above 330 ppm. Dissolve the CYA in the bucket with warm water and pour it around the pool’s edges. Test again after a day and if necessary, add more CYA.

Test Kits for Pool Stabilization

Though most pool test kits generally contain test strips or tools to test CYA, you may want to purchase a test kit separately; if that’s the case, here are a few recommendations:

Blue Devil: An extremely accurate kit that has enough to do 6-8 tests, the Blue Devil CYA test kit comes with a testing vial to determine acid amounts.

Pentair: The Pentair R151226 79 test kit tests CYA levels as parts per million and lets you comfortably do at least 10 tests.

If you don’t want to invest in a kit yet, you could take a sample from your pool to the local pool store and see if they can test it for you, instead.

The Final Word

Though lounging about in your pool is one of the most glorious feelings, it takes work maintaining your pool’s cleanliness and safety. Thankfully, products like CYA make the job easier.

CYA keeps pools exposed to sunlight safe from chlorine depletion, since the loss of chlorine will make your pool dirty and unsafe, with algae and bacteria claiming it.

See some of my guides on water quality:

Remember not to overdo the chlorine levels though – you don’t want the chlorine rendered ineffective in your bid to protect it.

Therefore, CYA is a completely necessary substance to have around if you have a pool, especially if you want a pool that’s protected and safe for you and your loved ones!

Last update on 2024-05-19 / 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 of 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!