How to Add Stabilizer to a Pool? The Easy Guide to CYA

A pool conditioner or stabilizer is a chemical used to protect your pool’s chlorine from the UV rays of the sun which makes chlorine evaporate. If you add the right amount at the right time, you’ll save a lot of time and effort purchasing more chlorine.

You will need to test your pool’s water chemistry and cyanuric acid levels to figure out how much stabilizer you need. Once you know the amount, add pool stabilizer to a bucket of fresh warm water and wait for it to dissolve. Then empty the bucket into your pool, ideally walking around the pool as you do so it is more evenly distributed.

This article will explain each step of this process in detail and discuss a few topics related to adding a stabilizer to a pool.

For instance, the different ways to test your pool’s CYA levels, when you should add the stabilizer, and how chlorine stabilizers work. So keep reading.

How to Add Stabilizer to Pool
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What is pool stabilizer?

The stabilizer used in a swimming pool is cyanuric acid, also known as CYA.

Basically cyanuric acid slows down the evaporation of chlorine from the pool’s water which takes place due to the ultraviolet rays of the sun – in other words it stabilizes the chlorine and gives i longer to work on the pool water.

Using cyanuric acid as a pool stabilizer is particularly important therefore if your pool is in full sun most of the day and is not covered with a solar pool cover otherwise the chlorine levels will quickly drop. An indoor pool does not need a pool stabilizer as the sun cannot affect it.

How often do you put stabilizer in a pool?

Generally you will only need to add stabilizer to your pool once a year. Pool stabilizer levels won’t go down during this period as the acid does not get used up. This longevity means you don’t need to spend a lot of time and effort in maintaining its levels in your pool.

Even so, it would be best if you kept an eye on your pool’s cyanuric acid levels from time to time. Every month or so, do a home test or have a professional test to make sure the acid levels aren’t going too high or low.

You should consider adding stabilizer if the level drops below 30ppm (parts per million).

How much pool stabilizer to add

Before you can start adding chemicals to your pool, you need to know how much you need.

The appropriate amount of stabilizer for your pool depends on its cyanuric acid (CYA) level. You can figure it out using an at-home liquid kit (see below) or by taking a water sample from your pool to a local pool store.

The package the cyanuric acid comes in will give you the manufacturer’s instructions for how much cyanuric acid you need to add for your size pool to bring the levels up.

I use In The Swim Pool Chlorine Stabilizer which you can buy on Amazon.

In The Swim Pool Chlorine Stabilizer and Conditioner - 10 Pound Bag

The problem with adding too much stabilizer

If you add too much pool stabilizer, you will reduce the effectiveness of sanitizing. Instead of stabilizing your pool to an ideal level, it will stop the chlorine from doing its job completely.

This phenomenon is called a chlorine lock, and it basically means the chlorine stabilizer is doing the exact opposite of what it is supposed to do.

Once you add too much chlorine stabilizer to a swimming pool, the only way to reduce it is by removing some of the pool water and adding in more fresh water. Not only is this a long process and expensive but it is also completely unnecessary.

You can avoid it by doing the correct homework and only adding as much chlorine stabilizer as is necessary.

how to lower cyanuric acid in pool

Pool stabilizer test kits

Ideally, you should be testing your swimming pool every week. If you use it regularly and want to maintain its chemical levels, weekly tests are essential.

However, going to a pool store every week isn’t very practical, so we’ve compiled a list of some of the best at-home test strips that you can use to keep an eye on the cyanuric acid level in your pool water.

Blue Devil CYA test kit

This kit has enough chemicals in it to do at least 6 to 8 tests on your pool. It is extremely accurate and will give you a clear picture of the chemical levels in your pool.

Blue Devil Cyanuric Acid Test Kit comes with a testing vial and easy-to-follow instructions. Figuring out your pool’s CYA levels won’t take more than 3 minutes with it.

Blue Devil B7112 Cyanuric Acid Test

Here’s how you can use it:

  • Fill the test stick with water up until the line marked ‘A.’
  • Add the solution provided until the line marked ‘B.’
  • Mix the solution and let it sit for 3 to 4 minutes
  • Look through the solution from the top and try to see the black dot. If you can’t see it, raise the stick above water level until it appears.
  • Read the number value on the stick that is closest to the water level. This is your pool water’s CYA reading.

Pentair CYA test kit

Pentair Cyanuric Acid Test Kit is another effective at-home test kit. You can use it for around ten tests with the same method as the Blue Devil kit.

Pentair R151226 79 Cyanuric Acid Test Kit

You add pool water to the solution provided in the product. Then move the test tube until you can see the black dot. Once you see it, make a note of the number closest to the surface. This is your pool water’s CYA reading.

Test strips

A good test strip will not only tell you how much chlorine is in your pool and the pH of the water but will give other readings too.

I use AquaChek 7-Way Pool Water Test Strips which include the CYA stabilizer level as well as free chlorine level, total chlorine, pH, total alkalinity, hardness and bromine level.

AquaChek 7-Way Pool and Spa Test Strips - Silver Pool Test Strips For pH, Total Chlorine, Free Chlorine, Bromine, Alkalinity, Total Hardness, and Cyanuric Acid - Water Quality Testing Kit (100 Strips)

How to add pool stabilizer

A pool stabilizer is an acid that dissolves slowly. It is extremely corrosive as well. Manufacturers often recommend that people add it directly to swimming pool water as it will eventually break down and dissolve into the water. However, this is a bad idea.

How to dissolve pool stabilizer

Irrespective of what the manufacturer’s instructions are, you should add a stabilizer by dissolving it into a bucket of warm water separately and then slowly adding stabilizer to pool by pouring the diluted solution around the edge of your pool.

Liquid stabilizer dissolves quicker than powder or pool stabilizer granules. This makes it easier to use. So if you have an option between these three types, pick the liquid stabilizer.

Why not add it directly?

how to raise cyanuric acid in pool

If you add the cyanuric acid directly to your pool, then with the possible high concentration you could risk damaging everything it comes into contact with. This includes everything from your skimmer to the delicate components of your pool filter and even the surface of your swimming pool.

Each of these parts is super expensive and will need to be replaced if damaged even a little bit by undiluted acid. On the other hand, diluting the stabilizer by dissolving it in water reduces its strength and makes it non-harmful.

Using stabilized chlorine instead of chlorine stabilizer

Stabilized chlorine is a product that combines both chlorine and pool stabilizer. So instead of adding chlorine to your pool and stabilizing once a year, you’ll do both together at appropriate time intervals.

You’ll be adding a bit of stabilizer every time you add chlorine. Many people see chlorine pool stabilizer as a way to kill two birds with one stone. After all, if you use this product, you don’t need to worry about adding any extra stabilizer.

However, if you choose to do this, you will need to do weekly or bi-monthly testing as the CYA levels can get too high.

Do all pools need a stabilizer?

Remember that stabilizer’s only purpose is to stop the sun’s UV Rays from eating away your pool’s chlorine. So it is reasonable to assume you only need to add stabilizer to pools that are exposed to the sun.

Adding a stabilizer to an indoor pool for example won’t benefit you in any way and it would be the same for an outdoor pool that was almost constantly in shade.

Also read: What does cyanuric acid do?

Can you shock your pool and add stabilizer at the same time?

You should add shock first and give it a chance to work before adding stabilizer.

Once the higher chlorie levels there will be after shocking start to reduce to a more normal level you can then add the stabilizer to protect the remaining chlorine from being used up by UV rays.

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It was probably the best money I spent that year as I have saved thousands by doing it myself.

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Pool care handbook

Frequently Asked Questions

Here are a few other common questions people ask.

Do chlorine pool stabilizers really work?

Chlorine stabilizers work for outdoor pools. If you’re using one, you don’t need to add an extra stabilizer, as you’ll be adding a little bit every time you add chlorine. It is an effective method to introduce both chemicals to your pool.

The only reason why chlorine stabilizers are met with hesitation is that they can cause a chlorine lock very easily. So you have to do regular cyanuric acid testing. However, you should be doing this anyway to ensure your pool has the right chlorine levels. So it isn’t a huge issue.

What’s the best time to use pool stabilizers?

Use a pool stabilizer whenever your pool’s CYA levels start dropping. Do regular testing using home kits or take a bit of your pool’s water to a local pool store and ask them to run the test. The right levels are between 30 and 50 ppm.

If your pool’s CYA levels are below 30 ppm, add some stabilizer using the method explained above.

What’s the best way to add a stabilizer to a pool?

As long as you aren’t adding an undiluted stabilizer directly to your pool, you can use whichever method seems easiest to you.

You can add it to your pool directly or combine it with chlorine. If you want to add it directly, you can purchase some from a pool store, dissolve it in water, and add the solution to your pool.

If you prefer adding it combined with chlorine, invest in a chlorine stabilizer. These are available in liquid form as well as in chlorine tablets.

How long after adding stabilizer can I swim?

Ideally you should add the stabilizer and run the pool pump for a short while (20 minutes or so) before swimming to allow the stabilizer to disperse around the pool.