Do Chlorine Tablets Raise The pH Of Pool Water?

When it comes to having a safe and clean pool, the use of chlorine can’t be over-emphasized. Chlorine is one chemical that one always needs to keep the pool water free from algae and bacteria. The chlorine tablet is not left out as it provides the pool water with great benefits as well. But, increasing the pH of pool water isn’t one of them. So the question remains: do chlorine tablets raise the pH of your pool water?

Chlorine tablets don’t raise the pH of pool water. Rather, it lowers the pH and the Total Alkalinity (TA) of the pool. This in turn will make the pool water acidic.

If you have been wondering whether your chlorine tablets can play, a dual role of sanitizing your water and also raising its pH, you would be getting the accurate answer from this post. This article has been put together to address the question that is asked by a lot of people. Get more information about chlorine and the pH of your pool water by reading further.

What is a chlorine tablet?

Chlorine tablet otherwise known as Trichlor is a sanitizing chemical for swimming pools. It can be used as a primary or secondary source of chlorine. This simply means it can be used alone or as a backup to a sanitizing chemical.

Can the swimming pool become acidic with chlorine tablets? Yes, when chlorine tablets are used alone because of their low pH, which is about 2.9, the pool water pH will be low as well and the water becomes acidic.

How does chlorine affect pool pH?

High chlorine levels decrease the pH of your pool water making it more acidic. The more acidic the water is, the higher the likelihood of corrosion. You should do your possible best to avoid corrosion as it will affect the surface of the pool, metal piping, and other components of the pool.

Does chlorine bring pH down?

Yes, since chlorine tablets otherwise known as trichlor is an acidic product, which means that it has a low pH level, it decreases the pool pH.

Do chlorine tablets raise the pH of the pool?

Generally, chlorine tablets can be used as an effective sanitizer for a swimming pool. It doesn’t raise the pH of the pool rather it lowers the pH of the pool. It does the same to the Total Alkalinity (TA) of the pool. Chlorine tablets do increase cyanuric acid levels.

It even becomes worse if it is the only source of sanitizer in your pool. The more chlorine tablets you add to your pool, the more likely you are going to have a low pH level. So, it’s not safe to use too many chlorine tablets as it can affect both the components of the pool and the swimmer’s health.

Reasons why chlorine tabs can’t increase the pH of a pool?

  • Chlorine tablets are acidic

This is one of the outstanding reasons why chlorine tablets can’t raise the pH of your pool. Chlorine tablets are generally acidic; this is just their natural state. So, it simply means that by adding them to your pool, the pH and alkalinity of your pool will simultaneously reduce. The best time to use it is when you want to reduce the PH and/or alkalinity of the pool. If you like using chlorine tablets as a lone sanitizing agent, you would need to do a pH test and balancing to get your pool to a safe state.

  • It creates a high chlorine level

Another reason is that the use of chlorine tablets creates room for high chlorine levels in the pool. You know the use of chlorine tablets is seen as a set-and-forget system. Chlorine tablets dissolve gently and once you get the right balance, you might forget about it without any worry about safety. But if the right amount is not used, of course, as earlier stated, the more chlorine in the pool water, the more it drives the pH low.

  • The pH of chlorine tablets is low

The chlorine tablets come with a low pH which is about 2.9. So naturally, adding it to your pool water will also reduce the pH level of the water as well. That’s why the more chlorine, the lower the pH level in the pool. So, when you use chlorine tablets as your main sanitizer, take more that it can potentially lower the pH, especially when the amount is high.

  • Problems associated with low pH caused by using chlorine tablets alone in your pool

Once chlorine tablets are used as a lone sanitizer, the pH of the pool will drop and when this happens it leaves the pool in a jeopardy. The following are the common issues that result from low pH:

  • Aggressive water

The first encounter will be the water turning acidic which becomes unfit for use. It would be an unwise decision to use the pool in this condition. If left unattended for a while, it may even damage the mechanical components of the pool.

  • It lowers the Total Alkalinity of the pool

Chlorine tablets will not only lower the pH of the pool, but will also lower the total alkalinity. This means the carbon and the bicarbonate levels in the water will be affected as well. The swimming pool will be below 80ppm in alkalinity which is against the 80-120 ppm ideal range. Such a low level of alkalinity can make the pool crack and etch. Moreover, any chemical you add to the pool at such a condition will greatly affect the pool, leading to a condition known as pH Bounce.

  • Causes Irritation to the users

As the water turns acidic, not balancing it will affect the swimmers. Using the pool like that will cause irritations of the eyes and mucous membranes. It affects the skin as well.

  • Damages to the pool liner

This will be great damage to the vinyl surface of the pool. The low pH caused by chlorine tablets will affect the vinyl walls and the floor. This will make the pool look old. The surfaces will become brittle and ripped.

  • Cyanuric acid becomes very high

Another side effect of using too much chlorine tablet or using it alone as a sanitizer is that it makes the cyanuric very high. The ideal level of cyanuric acid that is functional for a pool is about 30-50ppm. When it goes beyond that range due to low pH caused by the chlorine tablets it will weaken the sanitizer. As a result, you may be forced to add more chlorine to bring it to a balance. This might make the water green or cloudy. The bottom line here is that the cyanuric acid will be high and renders the chlorine sanitizer ineffective.

Factors that can raise the pH of pool

The fact that chlorine tablets don’t raise the pH of a pool doesn’t mean that other factors don’t do it. So if your pool water pH is high, the following factors might just be the cause:

  • Loss of carbon dioxide
  • Introduction of rainwater
  • The sanitizing chemicals in use
  • The rise in temperature
  • Algae in the water
  • High temperature

How to effectively raise the pH of a pool with fewer chlorine tablets

The truth remains that chlorine tablets aren’t just right to be the only source of chlorine in a pool. If you use them alone as your sanitizer, it could become terrible to the pool. It is effective when used as a secondary source. When used alone it will lower the pool pH and increase the cyanuric acid in the water which makes it bad for the pool. One advantage of using the chlorine tablets is that it dissolves slowly in the water, so the chlorine residual will be in the pool for a long time. Therefore, it is still good to use chlorine tablets for this reason. But you need to have a primary source of chlorine such as liquid chlorine (sodium hypochlorite) and use the tablets as a backup.

Liquid chlorine is less effective than chlorine tablets because it has no built-in cyanuric acid. More so, it doesn’t lower total alkalinity and even makes it easy to balance the pool as well. What you need to do to have a balanced pH level is to first test the pH of the water, then use the liquid chlorine as the main source of your sanitizer. Add little chlorine tablets as a secondary source and test the water again to know the pH level.

If the pH level of your pool is low, you can use sodium bicarbonate to raise it to the ideal range. With this, even when other chemicals like algaecides are added to the pool, they will not be rendered ineffective by high cyanuric levels.

Reasons why chlorine tablets are still preferable for pools

Everything comes with two sides; the good and bad sides. Though chlorine tablets tend to lower the pH of the pool water, other great benefits can be derived from using them in your pool. Some of these benefits include;

  • Dispense chlorine at a steady rate – This is one of the unique features of using a chlorine tablet in a pool. It dissolves gradually in the pool. This is a lot better than tossing a few scoops of chlorine granules into the pool. With the tablet form, there will be a continuous supply of chlorine in the pool for a while. Hence, the sanitizer will continue to attack contaminants in the water for a longer period. To achieve you will need an automatic chlorinator or a floater/dispenser. So the pool will always be with fresh and clean water for swimmers.
  • Ease of use – Unlike other forms of chlorine, the chlorine tablet is the easiest to use. You may not need to measure the tablet the way you need to measure other ones. Once you know the right gauge for your pool, all you need to do is to set the chlorine tablet, and you are done.
  • Easy to transport and store – The good thing about getting chlorine tablets for your pool is that you can easily transport them. Unlike the liquid form that can spill and ruin things even the skin, you can easily carry the tablet about. Moreover, they are light-weight and have excellent shelf life unlike others that their potency reduces by the day.

Can you swim in a pool with chlorine tablets?

Yes: with chlorine tablets present in the water, you can still swim. But you need to test the chlorine level to be sure it is good enough and safe for use. The chlorine tablets dissolve slowly in the pool water. So, it is usually safe to swim even when you have it in the pool. However, you need to avoid direct contact with it.


Chlorine tablets wouldn’t raise the pH of your pool, instead, they will reduce the pH and total alkalinity of the pool. Chlorine tablets aren’t too bad for pools but they need to be used sparingly. Again, to achieve a better-balanced pool for yourself, you shouldn’t make chlorine tablets the main source of your sanitizer it will lower the pool pH bringing along severe consequences.

So if you need a sanitizer that wouldn’t lower your pool pH but at the same time will be easier to balance the pH of your pool be, getting the liquid chlorine will be your best bet.

Chlorine tablet doesn’t raise the pH of pools. So, whenever you are trying to raise your pool pH, you need to exclude chlorine tablets from your list agents.

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