Stabilized Versus Unstabilized Chlorine – What’s the Difference?

As an aspiring or new pool owner, chances are you are a bit overwhelmed with all the new terms, techniques, chemicals, and the like you are expected to become familiar with. While it is true that pool ownership does entail a bit of a learning curve, it isn’t as scary or hard to understand as one might originally think. The most important aspect of pool ownership is testing your water. This is how you measure the levels of various chemicals and other substances in your water. It allows you to determine whether your water is safe to swim in and can help identify problems with chemical balance or substance buildup that need to be addressed.

The most important chemical you will use in your pool is chlorine. This is how your water is sanitized and kept safe for swimming. It might be frustrating to find out that there are a few different types of chlorine that you will need to familiarize yourself with when managing a pool. Today we are going to focus on stabilized and unstabilized chlorine. The difference between these two types of chlorine matters, so let’s start by discussing each in turn.

What is Unstabilized chlorine?

The easiest way to define unstabilized chlorine is to say that it is just plain chlorine that has had no cyanuric acid (pool stabilizer) added to it.

When unstabilized chlorine is exposed to the sun, the UV rays will rapidly break it down, rendering it unable to sanitize the water. When your chlorine is unstabilized, it will take a lot more chlorine to keep your pool water sanitized during periods of intense sunlight. You can maintain your pool without the use of a pool stabilizer, but you will need to check your water regularly and make sure you add enough chlorine to the water to keep pace with the breakdown via UV rays.

This all means that the unstabilized chlorine dissipates far more quickly than stabilized chlorine, and you’ll have to add more chlorine more often.

If you have an indoor pool, the issue of UV rays won’t apply and so you will most likely use unstabilized chlorine as the means to keep your pool safe and clean. This doesn’t mean that acid is not part of your chemical repertoire, but you will be using what is called muriatic acid, which is serves a similar function but is also very different.

 

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What is Stabilized chlorine?

So, since unstabilized chlorine is just plain chlorine, what is stabilized chlorine? Put simply, stabilized chlorine is chlorine that has also had pool stabilizer, or cyanuric acid, added to it. Chemically, cyanuric acid helps to keep chlorine stabilized and active and thus able to sanitize your pool water, even in intense sunlight. It doesn’t mean the chlorine won’t break down, but the stabilizer keeps it active in the pool water much longer than chlorine alone can.

You can often buy premixed solutions that already have the appropriate amount of pool stabilizer added to the chlorine. Or you can mix it yourself. Cyanuric acid is available in a range of different forms from liquid to powder. What will work best for you is a personal preference issue, but these are strong chemicals so you want to take safety precautions when handling them. Always follow manufacturer instructions when using these harsh and potentially dangerous chemicals.

 

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Pros and Cons

A lot of pool owners tend to use stabilized chlorine as it makes keeping the proper chlorine balance a lot simpler during those intensely sunny days of summer. Using a stabilizer with your chlorine will help it last longer and go farther. This means that you will need to refill drums or add chemicals less often, which will not only reduce your exposure to harsh chemicals but will also save you money on your chlorine needs. Stabilized chlorine is less prone to dramatic swings and for many makes it easier to maintain the proper chlorine balance.

This is not to say that pool stabilizer is without its issues or that you have to use this to keep your pool safe and clean. The thing about pool stabilizer is that, when too much is used, it can have the opposite effect, rendering your chlorine inactive. This can spiral out of control to the point where you can add as much chlorine as you want, but it will be immediately rendered inactive when it makes its way into the pool. It can also lead to issues with pH balance, which can throw your entire pool’s chemistry out of whack and fixing it can be a bit of a process. When this happens, you will need to do a partial drain of your pool to allow you to add fresh water to dilute the pool water.

It will take a lot more effort and chemicals to manage your pool with unstabilized chlorine, but it is not impossible to do so. If you have an indoor pool, unstabilized chlorine is likely to be the best option for you. Since your water will not be exposed to sunlight, it won’t have the same issues with breaking down in the UV rays as chlorine in an outdoor pool does. For outdoor pool owners, stabilized chlorine likely makes the most sense. This will make it easier to keep your pool water clean and safe. It will reduce the amount of chemical you have to add to keep the water sanitized and it will also save you money on your chemicals.

It must be stated once again that you if you choose to use pool stabilizer, it should be used with caution. There is most definitely such a thing as too much of a good thing where cyanuric acid is concerned. Overusing it will lead to huge problems. When cyanuric acid levels are too high, chlorine is immediately broken down and is no longer “free.” Free chlorine is chlorine that is available for sanitation. When this happens, no amount of adding chlorine will fix the problem. It will be rendered inactive as soon as it is absorbed into the water. It is vital that you only add as much as you need and no more. Always follow manufacturer instructions when using cyanuric acid to ensure that you use the correct amount to stabilize your pool.