A swimming pool is unlike anything else you would ever own. You can live in your house even though you don’t clean it. You can always ride a bike if you don’t clean it. 

But, can you swim in a pool that is not clean? Even if you can, you shouldn’t. A water body simply attracts various invisible parasites and pathogens, which make swimming pools unsafe for us.

Now, to make it safe, there is a regular need for Pool Sanitizer. Chlorine plays a crucial role in the components of a pool sanitizer. In this article, we are going to demystify one particular chlorine type, trichloro-s-triazinetrione.

What Is Trichloro-S-Triazinetrione?

Trichloro-s-triazinetrione is a dry solid containing the highest percentage of chlorine that is 90%. No other pool sanitizing pool contains such an amount other than gaseous chlorine. This chemical is often referred to as Trichloroisocyanuric acid or short-term Trichlorine and is commonly used in swimming pools.

Generally, you can find this in tablet forms which break down slowly and immerse in the pool with the help of an automatic chlorinator. The tablets reach a pH level of 3 so that the overall alkalinity and pH after use are subsequently reduced.

With 90% active chlorine, another main component of Trichlorine is cyanuric acid, which stabilizes your pool and provides protection against the sun.

Trichlorine can also be found in granular form but usually is used as shock treatment and much less popular- especially given the availability of other products with probably better shock treatment.

How Does It Work?

Trichlorine being a sanitizer takes charge of killing the germs in the pool. The tablets are dissolved in water and are changed into hydrochloric acid that combines with microbes which eventually breaks down their cell walls and kills them.

As this occurs, the contaminants are no longer able to invade their environment with bacteria and disease. They are therefore unable to replicate and create additional problems.

This “combined chlorine” is also known as chloramines, and chloramines are relatively harmless before they build up so much in the water, which is why you should shock your pool regularly.

Even though most chlorine products function, Trichlorine is more concentrated and performs more efficiently than others.

However, the chlorine product you should use must be according to your convenience. Every type has its pros and cons, and thus, it becomes essential that you bone up on and choose the perfect sanitizer.  

Advantages of Using Trichloro-S-Triazinetrione

●       Strong in Nature

Since it contains 90% chlorine, you must add a limited amount to the pool to get perfect results. It is advised to use one tablet at a time or 3ppm. 

●       “Set and Forget” Product 

Since they are slow-dissolving capsules, you do not have to manually apply chlorine to your pool daily, as you would for liquid chlorine.

●       Preservable

You can buy it in large quantities without worrying about potency. It would remain the same even if kept unused. 

●       Self-Maintaining

You don’t have to pour it every day, as it dissolves very slowly.

●       Cheaper Than Other Products

Anyone can afford this product easily, and it is cheaper than other products in the market.

●       Easily Available

It is relatively simple to transport since it comes in a variety of container sizes. Purchasing them locally is not difficult, and shipping costs are fair as well.

Disadvantages of Using Trichloro-S-Triazinetrione

●       Highly Volatile 

If exposed to Calcium Hypochlorite, which is commonly used for shocking, trichlorine can be explosive. Thus, you must handle it with care and avoid mixing Trichlor with the wrong chemicals because even the residue can cause a reaction.

●       Endorse the Process of Rusting

If not used as suggested, it can be hazardous. Trichlor’s high acidic nature can rust the pool surfaces easily. To avoid this, you should always use an automatic chlorinator while sanitizing. 

Properties of Trichloro-S-Triazinetrione

  • It is stabilized, which means it contains cyanuric acid, which protects it from the sun. This is nice because it is needed for daily chlorination, but frequent use significantly raises your cyanuric acid level. This will inevitably cause your chlorine to deteriorate.
  • Since it has a low pH, it can gradually lower the pH and alkalinity of your pool. If the pool is alkaline, this becomes surprisingly helpful, but the product can adversely affect the process if the pool is neutral or acidic. However, you can boost the pH level with baking soda.

Thus, while buying a pool sanitizer, you must keep your requirements in mind.

Why Is This Considered the Ideal Product?

Maintaining a correctly chlorinated pool is an ongoing challenge, and the type of chlorine you use will either make it simpler or more difficult. Trichlor tablets are an excellent option for a variety of purposes.

First and foremost, unlike calcium hypochlorite or liquid chlorine, which you must apply manually, you may simply drop these tablets into a floating dispenser or automated chlorinator and leave them to function.

You also don’t have to worry about calcium hardness problems because it doesn’t contain calcium (unlike calcium hypochlorite), and it’s one of the most affordable forms of chlorine available.

Cyanuric Acid

Since cyanuric acid constitutes a significant part of Trichloro-s-trizinetrione, it is essential to know its functioning. Or else you won’t be able to manage your pool the right way. 

As the chlorine dissolves slowly in water, so is cyanuric acid. The rise in its value weakens the effect of chlorine.

Cyanuric acid is a very stable molecule that does not dissolve readily in pools or spas. If the cyanuric acid level reaches the APSP limit of 100 ppm, a partial drain and refill are recommended.

Draining has the benefit of eliminating pollutants that have accumulated during the use of the pool or spa. It is recommended as a regular procedure for all pools and spas to keep total dissolved solids under control.

You can also switch to non-stabilized sanitizers like cal-hypo or liquid chlorine, or these days cyanuric acid remover is also available. 

Why Shouldn’t It Be Used for Pool Shocking?

Contamination of chloramines on the pool surface can result in a muggy and chlorine-like smell. In addition, it can interfere in the proper functioning of free active chlorine provided the fact that it can cause skin irritation to the swimmers.

Therefore, there is a need to shock your pool to remove such contaminations from it. For this process, you need to put ten times more chlorine as there are chloramines. Any chlorine can be used for this purpose, but have you thought of the other chemicals going into your pool water in large amounts mixed with chlorine?

A classic example is shocking with trichlor granules. The amount of chlorine you will be using would equate to the amount of cyanuric acid in the pool. Even though it is made for protection from the sun, its presence would still make it difficult for chlorine to work. Therefore, you should avoid certain products.

Calcium hypochlorite and Sodium hypochlorite are the right choices. They are unstabilized and are specially made for pool shocking.

Trichlor Chlorine Alternatives

There are ample choices to buy chlorine products for the pool. All of them are more or less effective. But Trichlo-s-triazinetrione and Dichlo-s-triazinetrione are the only options that are stabilized with Cyanuric Acid. However, cyanuric acid can be added manually to the pool along with normal chlorinator like-

●       Sodium Hypochlorite

Sodium hypochlorite is a liquid that contains approximately 10% available chlorine. This compound is present in household bleach but at a much lower concentration of 5% available chlorine.

●       Calcium Hypochlorite

As it’s widely called, Cal-hypo is typically available in granular form, but you can also find it in tablet form. It is possibly the most common because it contains between 40 and 80 percent usable chlorine.

●       Lithium Hypochlorite

This is a granular sanitizer with approximately 35% usable chlorine. It disintegrates easily, providing a powerful shock with minimal build-up. However, it is generally more costly and, of course, less efficient than the others.


The main fact is that you can use any sanitizer you want, irrespective of its functions. The distinction is that some products are more efficient or convenient to use than others, and Trichlor is one of them.

Trichlor tablets are the most common ones. Because of the “set and forget” aspect of tablets in general, they’re great for everyday chlorination, but they do add cyanuric acid to your tub, which may throw your chemistry off.

Therefore, you must know that whatever you choose, make sure you’re checking your water and keeping your pool in good shape regularly. 

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