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The Ultimate Guide to Add Chlorine To Pool


There are lots of things to know about a pool. Balanced chemical levels and the application of some chemicals are also vital to its operation. A pool owner must know how to add chlorine to pool since this chemical is necessary to keep a pool clean from the inside and out. One of the most well-known pool sanitizers is chlorine, you can use it to sanitize, disinfect, and even oxidize, which are all important processes in pool cleaning and maintenance.

One of the most important factors that should be remembered in having a clean pool is the right amount of chlorine to be used and applied. Once you have made sure that levels are of the required range, and there is a good residual of free chlorine, then it is not too far to have a healthy and safe pool where bathers can swim in. In this article, we will discuss what chlorine is, its types, and how to add chlorine to pool, so if you are a new pool owner, there are lots of facts to learn here.

Swimming Pool

Part 1. What Does Chlorine Do for a Pool?

Before we get into the steps on how to add chlorine to pool, we need to first figure out what does chlorine do for a pool. Chlorine is used to sanitize pool water where it can kill lots of microorganisms and may ensure you have a 99.9 % reduction of these bacteria in less than thirty seconds.

It is also used as a disinfectant which can kill all harmful and even infectious microorganisms that can cause sickness to bathers, and may ensure 99.999 % reduction of these microorganisms in less than 10 minutes. It can also be used as a sterilizer and can kill all living microorganisms with a 99.999 % reduction in a short time as long as bacteria are still present.

It can also be used to oxidize, destroy, break down, and even chemically burn up non-living substances, and in the process, the oxidizer will take electrons from an oxidant, which is why the oxidizer is reduced.

Chlorine is very vital in pool water since it can deal with both living and non-living contaminants which may damage your pool and which may also affect pool bathers’ health. Chlorine is mainly used to kill germs and microorganisms that are said to be harmful, some can even cause you to acquire diseases. But it is also important that chlorine is not just responsible for fighting the bathers’ wastes, but also oxidants which can be present in the water like nitrogen compounds, metals, and a lot more. The said oxidants reduce chlorine levels in the water, which is why it is important to always monitor chlorine levels, and add doses once needed. It is recommended to supplement chlorine with a sanitization system, enzymes, or a secondary oxidation.

Part 2. How to Add Chlorine to Pool?

Now that we have enough ideas on what chlorine can do for a pool, it is now time to figure out how to add chlorine to pool. Well, even with these things, there are lots to consider such as the size of your pool, its location, how often it is used, or even the type of chlorine that you usually use for your pool. In this part of the article, we are going to take the step-by-step procedures on how to add chlorine to a pool based on the type of chlorine that you can use.


Trichlor or trichloro-s-triazinetrione is one type of chlorine that is stabilized to fight the UV rays of the sun. This is usually seen in tablets, one is the 3-inch one and the other is the 1-inch one. This is why home pools usually use it, it is really easy to use. This type of chlorine will require you to use a feeder so that the dissolution of tablets will be regulated. Ensure you have read all the indicated precautions on the labels of the products before proceeding. For trichlor tablets, it is essential to know that they should not be added to the skimmer since they are acidic, the use of chlorine floaters to add chlorine to a pool is also not recommended. And it must be remembered that the amount of chlorine to be added depends on how huge your pool is. In general, you have to conduct chemical level testing first before adding chlorine to your pool, so it will not be overdosed.

3 inch Chlorine Tablets for Pool

2. Chlorine Granules

The next type of chlorine is the granular form. Well, when you use this type of chlorine, the process of how to add it to a pool is really easy. You have to measure the chemical, start dissolving it in a bucket, and then start adding the dissolved chlorine around the perimeter of your pool. You should not directly add chlorine to your pool skimmer. Before adding any type of chlorine to your pool, the alkalinity and pH of your pool must be initially measured. Aside from preparing a bucket, you also have to get a stirring stick, and a measuring cup as well. When adding chlorine to your pool, regardless of the type, always wear protective gear like gloves and goggles. To easily guide you, the steps are:

  • Test your pool water to determine the level of free chlorine available, also determine the amount of chlorine that you have to add to the pool.
  • Using the bucket, stirring stick, and measuring cup, start mixing the chlorine. You have to fill the bucket with three-quarters of the water from your pool, and then add the chlorine granules as calculated, make sure to add them slowly. Using the stick, stir the mixture and make sure that all chlorine granules are completely dissolved.
  • Then, you can now add the chlorine to your pool, do it slowly, and make sure the whole perimeter is covered.

Pool Chlorine Granules

3. Liquid Chlorine

Well, liquid chlorine is the easiest type of chlorine to add to your pool. In adding liquid chlorine, you just have to make sure the level or amount that you will be adding is as required, and then slowly pour it into your pool’s perimeter. You can also use an inlet of your pool, the one that is responsible for pumping water to your pool and pouring the liquid chlorine into it.

Part 3. How To Maintain Chlorine Levels In Pools?

To make sure that chlorine levels needed in your pool are always maintained, you have to conduct testing frequently. It will keep your pool to be healthy, safe, and even adequately chlorinated, and of course, safe for bathers to swim in. You have to use testing kits every day and conduct testing two to three times a day, especially if you meet lots of bathers all day. On the other hand, in case your pool is not used all the time, you can execute a test once a week.

To ensure that test results are effective, you have to measure the chlorine levels and pH. You can only maintain proper chlorine levels with a balanced pH. Once you have noticed that there is a quite decrease in the level of chlorine, you should add chlorine immediately. The right level of chlorine in pools should be in the range between 1 and 3 ppm, while in hot tubs and spas, it must be 4 ppm or higher.

PH Level

Part 4. FAQs

1. How Often do You Need to Put Chlorine in a Pool?

You have to add chlorine in granular or tablet forms constantly. On the other hand, you have to shock your pool every two weeks using a higher dose of chlorine. This will raise the level of pH, and is also important especially if the weather is too hot or too sunny when chlorine can easily break down.

2. How Much Chlorine Do I Add to My Pool Per Gallon?

If you are about to use chlorine tablets, you have to add one 3-inch tablet of chlorine for every 10,000 gallons of pool water. This is the best amount especially if you are shocking your pool regularly every week.

3. Do I Add Chlorine or Shock First?

When there is a low chlorine level, or your pool water is cloudy or hazy, it means that you have not shocked your pool for quite a while. So, the initial step that you have to do is to shock it. It is recommended to do shocking at night since no sunlight will deplete the level of chlorine present in your pool water.

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