Will Stabilizer Damage a Vinyl Pool Liner?

Written by Michael Dean
March 1, 2024

adding stabilizer to a vinyl liner swimming pool

If you have a vinyl pool liner, you probably already understand that a lot goes into taking care of it. Unfortunately, there are some chemicals you can’t use in a vinyl liner pool as they may damage the liner. Cyanuric acid, or pool stabilizer, is an important ingredient in your pool chemical concoction, but does stabilizer damage your vinyl liner?

In this article, I will review whether a stabilizer like cyanuric acid will damage a vinyl pool liner. Let’s get into it.

Main Takeaways 

  • Stabilizer will not damage a vinyl pool liner if you dilute the CYA beforehand.
  • The recommended CYA levels for pools with vinyl liners should fall between 30 and 50 ppm.
  • Sharp objects, chemical imbalances, not pre-dissolving chlorine, draining the pool, and improper installation can damage your pool liner.
  • Keep your pool covered when not in use to protect the liner, and act promptly to repair it if you notice any damage to the material.

Will Stabilizer Damage a Vinyl Pool Liner?

Pool owners are right to be concerned about the chemicals that can damage their pool vinyl liner, especially if they are acidic. But don’t worry. When it comes to stabilizer or cyanuric acid (CYA), although it is an acid, it is pretty weak. It would take an extremely high concentration applied directly to the surface of the liner to damage the liner in any significant way.

However, that doesn’t mean you shouldn’t be careful while adding cyanuric acid to the pool water. As a top tip, no matter the strength of the chemical you’re handling, I always recommend adding it to your water with care and caution. One way to do this is by pre-dissolving the chemical in a bucket before adding it slowly to the pool.

How to Add Cyanuric Acid So It Doesn’t Damage Pool Liner

Here’s my step-by-step process for adding stabilizer to your vinyl pool so it doesn’t damage the liner.

Step One: Test Current CYA Levels

Before adding the stabilizer to the water, you must establish your current CYA levels. To test this, use fresh test strips or a liquid test kit – whatever you prefer.

Step Two: Calculate Required Levels

Ideally, the recommended CYA levels for pools with vinyl liners should fall between 30 and 50 ppm. So, if your CYA levels are below this range, it is time to add some cyanuric acid to help protect your chlorine from the sun’s UV rays. Calculate how much CYA you need using my stabilizer calculator.

Step Three: Add the Stabilizer

Now, it’s time to add the product to the pool, but don’t just pour it in! Whether using a granular product or a liquid stabilizer, pre-mix it in a bucket (adding CYA to water, and not the other way around) before pouring it into the pool. Aim for a 1:10 dilution ratio (one part stabilizer to ten parts water) and add it gradually. Do not add it directly to the pool, as it will create concentrated pockets of cyanuric acid that might damage the liner over time.

Step Four: Run the Pump

Run your pool pump for the next 8 hours to ensure the stabilizer thoroughly dissolves and circulates through the entire pool. Then, retest the water after 24 hours to ensure the CYA has reached a range between 30 and 50 ppm, and make any adjustments if needed.

And now, you’re all set! It’s important to regularly monitor your cyanuric acid level throughout the season along with other chemicals and maintain it for optimal pool health.

Other Ways You Can Damage Vinyl Pool Liner

Beyond careless use of pool stabilizer and other acids, there are several other ways you can unintentionally damage your vinyl pool liner. Here are some ways to keep in mind to avoid making this grave and expensive mistake!

Sharp Objects

Be careful with the use of sharp objects in and around the pool. Clear anything with sharp edges away from the pool, such as rocks, jewelry, and gardening tools. If you have pets, trim their nails and train them to get out of the pool in a manner that’s safe for both your pets and the pool.

Chemical Imbalances

Chemical imbalance is very harmful to the lifespan of your liner. pH levels outside the ideal range of 7.2 to 7.8 can weaken the vinyl liner, or excessive chlorine above 3 ppm can bleach and corrode it.

Not Pre-Dissolving Chlorine

If you use liquid chlorine, you can freely pour it around the perimeter of your pool. But if you use granular chlorine or tablets, you must always dissolve it in a 5-gallon bucket of water first. Then, pour it slowly around the pool and run the pump to ensure the chlorine doesn’t collect on the bottom and destroy the vinyl.

Draining the Pool

Avoid draining your vinyl liner pool if you can. The liner is meant to be underwater at all times. When exposed to air, the vinyl will dry out, causing it to shrink and crack – especially when it comes to older liners. If you absolutely must drain your vinyl pool for any reason, try to leave at least 6 to 12 inches of water to protect the liner as much as possible.

Improper Installation

Of course, you must install the liner properly in the first place. An improperly installed liner can result in unsightly wrinkles and folds, which may put stress on the material, increasing the risk of tears. Make sure a professional installs the pool liner to avoid such issues.

How to Maintain CYA Levels

As with any other chemical, it is important to maintain CYA levels to ensure the health of your pool. Here are my top tips on how to maintain your CYA levels.

Regular Testing

You should test your CYA levels once a week in the beginning. Keep track of the test results and record the numbers to determine the frequency of adjustments needed. As time goes on, if your CYA levels do not deplete as often as every week, you can probably get away with testing once every two weeks or so.

Lowering CYA Levels When Needed

If your hand slips or your calculations are off and you end up with CYA levels above 50 ppm, you’ll need to partially drain and refill your pool to lower the CYA levels.

Limit Sun Exposure

If your pool receives a lot of direct sun exposure, you’ll have to be more proactive with adding stabilizer to the swimming pool. Alternatively, you could install shade sails overhead to limit direct sun exposure and shield the pool with a pool tarp when the pool is not in use.

Check Other Chemicals for CYA

When using other pool chemicals, read their labels to see whether or not they contain CYA. This is especially the case with chlorine, as stabilized chlorine, like trichlor and dichlor, contains CYA. If you do not check your other chemicals for CYA, you may accidentally double the amount of CYA in your pool!

How to Repair Liner Damage

The truth is, no matter how well you protect your liner, some damage may occur. But the good news is that you can often repair liner damage without replacing the entire thing! Here are four options for repairing liner damage, ranging from small punctures to larger tears.

Vinyl Patch Kit

Depending on the size of the tear, it is possible to repair the small punctures under 2 inches with a vinyl patch kit specifically designed for vinyl pool liners. If this is the case, all you have to do is locate the hole, clean the surrounding area thoroughly, and ensure it is dry. Then, select the right size vinyl patch, apply your adhesive, and press the patch firmly over the hole.

Underwater Tape

If you don’t have access to a vinyl patch kit, you can also find waterproof tape suitable for underwater repairs of small punctures. This is a quick and easy option for minor damage.


Peel-and-stick patches work just like underwater tape, but these patches are made of vinyl – just like your pool liner! To use these patches, simply peel off the back and place the patch over the leak. These patches work best for small leaks and punctures.

Professional Repair

In cases of extensive damage or tears larger than 3 to 4 inches, you might need professional help. Pool repair technicians have the necessary expertise and tools to handle larger, more complex repairs, thus ensuring a proper seal.

Get My Free Pool Care Checklist

Download my free, printable pool maintenance checklist to help you accomplish regular pool care tasks for any type of swimming pool.

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Look After Your Liner!

By following the proper steps and caring for your liner, you can maintain and ensure a long and healthy life for your pool liner, which will keep your pool looking beautiful for years to come. And don’t worry too much when using cyanuric acid. As long as you pre-dilute the chemical before adding it to the swimming pool, the acid is weak enough that it won’t damage your liner.

Any more questions about vinyl liner care? Drop me a message!

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