2024 Pool Chlorine Calculator: Free & Easy to Use!

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Instructions for Using the Pool Chlorine Calculator:

Whenever you test your pool water chemistry, chances are you will need to use the pool chlorine calculator (below) to figure out the dose required to top up the difference between the ideal Free Chlorine (FC) and the actual Free Chlorine (FC).

Please follow instructions as under:

1. Select Chlorine Type: Choose the type of chlorine you plan to use for your pool from the dropdown menu. Options include Household Bleach, Liquid Chlorine, various forms of Cal Hypo, Trichlor, and Dichlor.
2. Enter Pool Details: Input the volume of your pool in gallons (Gal) in the “Pool Volume” field. Then, provide the current level of Free Chlorine (FC) in parts per million (ppm) under “Existing FC” and the desired or target FC level in ppm under “Target FC”. Target FC, should typically be 4-5 ppm.
3. Click Calculate: After entering all the required information, click the “Calculate” button. The calculator will process your inputs and provide the recommended dose of chlorine in ounces based on your pool’s volume and desired FC levels. In case of Bleach and Liquid Chlorine, please convert the ounces to fluid ounces or gallons as required.
4. View Results: Once calculated, the recommended dose will be displayed in bold below the calculator. It will specify the amount of chlorine in ounces to add to your pool of the selected chlorine type.
5. Apply Chlorine: Use the calculated dose as a guide to add the appropriate amount of chlorine to your pool to achieve the desired FC level.
6. Note: Always follow safety precautions and manufacturer instructions when handling and adding chemicals to your pool.

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Role of Chlorine in Pool Sanitization

Chlorine is possibly the most effective and affordable chemical for pool sanitization & disinfection. Chlorine keeps a check on the micro-organisms in the pool so that you can have a safe & enjoyable swim.

Pool Chlorine is essentially a chlorine based compound that reacts with the pool water to form a weak acid called Hypochlorous Acid (HOCL).

The Hypochlorous Acid (HOCL) sanitizes & disinfects by killing the viruses, germs, bacteria & algae. The acid penetrates the cell walls of the pathogens and makes the cell’s protein backbone dysfunctional. 

In addition Chlorine is also an “oxidizer”. Which means that chlorine can break down and destroy non-biological contaminants too!

The chlorine in your pool that still has the power to kill bacteria is called “Free Chlorine (FC)”. The chlorine that has already been spent is called “Combined Chlorine (CC)”. Together they are known as “Total Chlorine (TC)”. It is important to know this as testing kits only give TC and FC levels.

Pool Chlorine Types

There are four pool chlorine types that are commercially available and are quite popular. Two are unstabilized and two are stabilized. These are:

1. Unstabilized Chlorine
   1. Sodium Hypochlorite (Liquid Chlorine)
   2. Calcium Hypochlorite (Cal Hypo)
2. Stabilized Chlorine
   1. Dichloro-S-Triazinetrione (Dichlor)
   2. Trichloro-S-Triazinetrione (Trichlor)

Sodium Hypochlorite (Liquid Chlorine)

Sodium Hypochlorite (Liquid Chlorine) is the salt of Sodium with Hypochlorous Acid. It is sold as a 10-12.5% solution of Sodium Hypochlorite in water, hence the name Liquid Chlorine. It is just a stronger version of the household Bleach, which is a 6% solution.

Calcium Hypochlorite (Cal Hypo)

Calcium Hypochlorite (Cal Hypo) is the salt of Calcium with Hypochlorous Acid. It is usually sold as a granular powder but is also available as “slow dissolve” tablets. Cal Hypo, for pool use, typically has 48% to 73% Available Chlorine (AC) depending on the brand.

Dichloro-S-Triazinetrione (Dichlor)

Dichloro-S-Triazinetrione is better known as Dichlor. It is usually sold as a granular powder but can also come as tablets. Dichlor is manufactured by the chlorination of Cyanuric Acid (CYA). The chemical formula of Dichlor is (C(O)NCl)₂(C(O)NH).

Trichloro-S-Triazinetrione (Trichlor)

Trichloro-S-Triazinetrione is better known as Trichlor. It is most commonly sold as 1” or 3” tablets for sanitizing home swimming pools. Trichlor is the richest source of chlorine as it has more than 90% available chlorine.

Trichlor is manufactured by the chlorination of Cyanuric Acid (CYA). The chemical formula of Trichlor is (C3Cl3N3O3). In the original powder form, it is used as a disinfectant, bleach or processing chemical, in some industries.

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Thank you very much for reading the post. I do hope you found it informative and helpful.