How to Chlorinate a Small Pool

By Greg Jarvis | Last Updated: September 7, 2022

Your primary responsibility as a pool owner is to keep the water pool clean, and the best way to do it is by adding chlorine. However, you don’t just add it. You need to maintain the right level of chlorine to make the water safe for the swimmers. Chlorine tablets are the perfect solution in keeping the normal level at 2 to 3 parts per million (ppm). Add the tablets to an automatic dispenser to ensure even distribution of the chemical.

Aside from utilizing tablets, it would help if you sanitized your pool every 1 to 2 weeks using a granular or liquid chlorine shock treatment. If you’re working with chlorine in tablet, granular, or liquid form, read the instructions carefully and follow them strictly. In this how-to chlorinate a small pool guide, we will discuss chlorinating the water using the granular and the tablet form.

What You Need:

  • Gloves and eye protection
  • Chlorine tablets
  • Pool water test kit (for checking the pH)
  • Chlorine dispenser

Steps on Adding Chlorine in the Pool Water

Step #1 Put on your Protective Gear

Before you start adding chlorine tablets in the pool, make sure to put on your protective gear. Wear reliable protective goggles and thick gloves. If you are treating an indoor pool, ensure the area is well-ventilated before opening a chemical container.

Caution: Be extra careful when adding a liquid or granular chlorine. Wear long-sleeved shirts and pants and take care not to spill the chlorine.

Step #2 Prepare the Chlorine Tablets

One of the most popular ways of chlorinating the pool is by the use of chlorine tablets. They are easier to add, last longer, and are safer on pool liners than liquid solutions, best utilized as shock treatments. Tablets dissolve slowly, unlike granulated chlorine, which ensures equal distribution.

Note: Chlorine tablets can be purchased online or at a pool supply store. Tablets are available in 1 inch (2.5 cm) and 3 inch (7.6 cm) sizes. Larger pills are the preferable choice. They’re easier to handle, last longer, and cost less than 1 inch (2.5 cm) tablets.

Step #3 Calculate Pool’s Volume

To figure out how much chlorine to add, you’ll need to calculate the volume of water the pool can hold. To get a rough estimate, measure the length and width of your pool and its average depth, then multiply the length (L) by the width (W) by the average depth (H). If you have a circular pool, measure its diameter, divide it by two to get the radius, and then use the formula πr2h, where r is the radius and h is the average depth.

You may also find the volume of your pool by downloading an app or using an online calculator.

Step #4 Check the Water Pool to Determine the Amount of Chlorine to Add

Before chlorinating your pool, use a pool water test kit to check the pH and chemical levels. Read the product’s instructions; the label will tell you how much to apply based on the volume of your pool to get the desired chlorine level in ppm.

  • Multiple chlorine readings will be displayed on your test kit. Free accessible chlorine is active and kills bacteria, whereas combined chlorine is the quantity of chlorine used to kill germs. If you use your pool regularly, test it every day and keep the free accessible chlorine level between 1 and 3 ppm.
  • Maintain a spa or hot tub with a free accessible chlorine level of roughly 4 ppm.
  • Round up to the closest 5,000 gallons at all times (19,000 L).  For example, say you have a pool that holds 33,760 gallons (127,800 L), your present chlorine level is about 0 ppm, and your product instructs you to add 1 tablet per 5,000 gallons (19,000 L) to raise chlorine levels by 1 ppm. To attain a value of 2 ppm, 14 pills would be required.

Step #5 Use a Chlorine Dispenser

Tossing tablets into the pool will not solve the problem. Instead, chlorinating skimmer, a floating chlorine feeder, or other automatic dispensing system is recommended. Drop the tablets in the feeder’s cartridge and wait for them to dissolve. It normally takes a few days.

  • If your pool’s chlorine level is less than 1 ppm or greater than 5 ppm, you can swim while the tablets disintegrate. They are intended to be used on a regular and ongoing basis.
  • Chlorine dispensers are available online and at pool supply retailers. Simple floaters are cheap, but skimmers that clear trash and dispense chemicals can cost hundreds of dollars (U.S.). 

Step #6 Adding Cyuranic Acid to Stabilize Chlorine

Cyuranic acid is a stabilizer that extends the life of chlorine. If your chlorine is labeled “stabilized,” “dichlor,” or “trichlor,” it already contains cyuranic acid, and no further treatment is required. If not, buy liquid or granular cyuranic acid, dilute it following the instructions on the package, and add it to the pool.

  • The appropriate amount to add varies depending on the product. To get a level of 10 ppm, add around 4 pounds (1.8 kg) of cyuranic acid per 10,000 gallons (38,000 L) of water. It is advised to keep cyuranic acid levels around 50 ppm.
  • When mixing and applying pool chemicals, remember to wear goggles and gloves.
  • Cyuranic acid should not be used in a spa or hot tub.

Steps on How to Shock the Pool

While tablets are ideal for normal chlorination, shock treatments are often liquid or granular. The procedure for application and the amount vary, so it is best to check it out to a pool supply store staff and read the product’s instructions thoroughly.

Step #1 Combine the Product with Warm Water

Fill a large, clean bucket with the amount of warm water specified in the instructions, if necessary. Then carefully add the required amount of chemical to avoid spilling or dispersing fumes. Slowly stir the solution until the liquid product is uniformly distributed or the granular product is completely dissolved.

When diluting or administering chlorine shock treatments or any other pool chemicals, always use safety gear.

Step #2 Add Chlorine to Reach the 8 ppm Level

Do not forget to test the pool water before adding the chemicals to it. After measuring, if needed, dilute the correct quantity of chemical, add it portion by portion to the pool. Slowly pour it as you walk around the pool’s perimeter to make sure to distribute it evenly.

Note: Never add undiluted shock treatment into the water unless it is specified in the instructions.

It is more effective to add the shock treatment at night. Sun UV rays may break down chlorine, making the shock treatment less effective if you add it during broad daylight.

Step #3 Measure the pH of the Pool’s Water

The chlorine shock treatments normally have a pH of 10 or higher. This will throw off the pool’s pH levels. If needed, you will be instructed to add an acidic pool water amendment to counterbalance the high pH of the shock treatment.

Step #4 Let the Chlorine Level Reduce to 5 ppm Before Using the Pool

Shock treatments raise free accessible chlorine levels to 8 to 10 ppm, above the safe swimming threshold. Some shock treatments work fast, and swimming can be resumed after only 15 to 20 minutes. You’ll have to wait 4 to 24 hours for other products.

Step #5 Shock the Pool Every 1 to 2 Weeks

Regardless of how frequently you use your pool, shock it at least every two weeks while it is in use. If your pool receives a lot of use, shock it once a week. Additionally, shock it after pool parties and if it has been contaminated, such as after a restroom mishap.


The process of how to chlorinate a small pool may look complicated at first, but it’s not. Just make sure you follow the instructions carefully so you can effectively chlorinate the pool water. Your safety is essential, so make sure you put on your gloves and eye protection before you start working. The chemicals are harmful to your skin and eyes, so you need to protect them.

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