How Much Chlorine To Add To A Swimming Pool

Adding the right amount of chlorine to the swimming pool can be a daunting task. Chlorine is an important agent to be used in the pool on regular basis for sanitization. Think about the sparkling water in the pool which is completely free from any pathogen. How amazing would it be to take a worry-free dip into such clear water and swim freely!

The visions of happy swimmers start to dance around our heads when we think of pool treatment with chlorine. It is the most crucial part of pool maintenance. If you are running a pool facility, it is mandatory to treat it regularly with chlorine and keep the pool safe for swimmers above all else.

With everyday use, a lot of organic materials start to build up inside the pool. It is not as easy as simply putting chlorine in pool water and calling it a day. A balanced amount of chlorine has to be determined in order to decontaminate the pool as well as make it safe for swimmers.

The first step starts with determining the pH level of the water as chlorine might lose its effectiveness if not added at the right pH. For proper disinfection, routine chlorine should be used to kill everyday built-up of microorganisms. Let us understand a few facts before we proceed further to the main process.

What Is Free Chlorine In A Pool

Chlorine comes in many forms. To add chlorine to the water, you must first test the pool water for a proper check. Test the water to first determine the chlorine residual. Accordingly, figure out the amount of chlorine to be further added.

Chlorine comprises of two components – organic and inorganic chlorine. While treating pool water with chlorine, it is usually the chlorine which reacts with the bacteria and contaminants. Hence, Free Available Chlorine (FAC) is the portion from the total amount of chlorine that remains in the chlorinated water which has not yet reacted with contaminants and is free to go and work on pathogens. Most of the test kits in the market measure Free Available Chlorine in pool water easily.

Total Chlorine VS Free Chlorine

As the free chlorine starts to act, it gets converted into a combined one. Now the sum total of both the free available and combines chlorine is called as Total Chlorine. Now chlorine represents a portion of total chlorine that has not started to work yet but free to do so. It is actually the main agent to do the real job of pool cleaning and sanitizing.  On the other hand combined chlorine is ineffective and does not contribute to sanitizing the pool water. It is only free and total chlorine that take part in the sanitization process and aid in making pool water pathogen-free.

There are many types of chlorine to be used for chlorination. We can select from chlorine gas, sodium hypochlorite or liquid bleach, cyanuric acid and solid chlorine tablet. Automatic chlorine feeders are quite popular among swimming pools owners. They are super easy to use and meter out exact amount to be used in pool automatically.

Regardless of what you wish to use, the most important thing to remember is to maintain optimal chlorine level in water which should be in range of 1.0 to 3.0 parts per million.

Listed below are basic steps to assist you in determining the amount of chlorine to be added to the swimming pool for healthy pool health.

Step 1. The foremost step is determining the type of chlorine you wish to use. Chlorine tablet that kills microbes come in standard sizes of 3-inch, 1-inch and sticks. The most common is the 3-inch tablet. The active ingredient in all of these is the same except for its concentration.  1-inch tablets are the best suited to above-ground pools. They are quick to dissolve than the 3-inch tablets or chlorine sticks. Chlorine stick, on the other hand, takes far more time that 1-inch and 3-inch tablets.

Step 2. If you are using Cyanuric acid, exercise caution. Cyanuric acid is the stabilizing agent in chlorine. Make sure to test the water levels as cyanuric acid needs to be maintained at a level not exceeding 40 ppm. If it goes any higher, chlorine won’t be able to perform and will lose its sanitizing ability.

Step 3. Alternatively, if you are using liquid sodium hypochlorite or solid calcium hypochlorite, first check the pH of pool water. These two chemicals are highly reactive and may increase the overall water pH if used in sufficient quantities.

Step 4. Automatic feeders are an excellent medium to chlorinate water and can be purchased from any pool supply distributor. You can dissolve chlorine tablet or stick of your choice in the chlorine feeder and let it determine as well as control the precise amount of chlorine being added in pool water.

Step 5. Calculating the exact amount of chlorine to sanitize can be tad tricky but nothing too complicated. You need to determine the total gallons in the pool and run some calculations. That can be simplified by using any online pool calculator. Once you know the total volume of water present in the pool then use this easy formula.

“For every ounce of chlorine that we use in 75,000 gallons of water, it gives 1 ppm. That comes to be 0.013 ounces of chlorine for every 100 water gallons”

Step 6. Right after you have chlorinated the water, run a test for its pH. It is the major factor that determines how well chlorine will sanitize. The pH should be in the range of 7.2 to 7.6.

Step 7. Test the water twice a week at least to ensure good pool health. Maintain your pool’s free available chlorine level at 1-3 ppm. This is the best range to ensure low-maintenance pool. Schedule weekly pool maintenance tests for proper pool maintenance.

Things to remember

  • Chlorine might become inactive as soon as it binds to chemicals like ammonia and nitrogen. Shock treatment should be given to eliminating combined chlorine.
  • If pH level goes high, lower it by using muriatic acid. Retest the water and re-adjust the pH as needed.