Adding chlorine to your pool is essential for keeping it safe and clean. Chlorine kills bacteria, algae, and other organisms that can make their way into your pool and can cause illness and other health problems. Liquid chlorine is one of the most common forms of chlorine used to sanitize pools. The amount of liquid chlorine you add to your pool depends on the size of your pool and the amount of chlorine you need to maintain a healthy chlorine level.
Size of the Pool
The size of your pool is an important factor when determining how much liquid chlorine to add. Smaller pools, such as a 20-foot round pool, require less chlorine than larger pools. Generally, a 20-foot round pool requires 1.5 to 3 gallons of liquid chlorine per month to maintain a healthy chlorine level. For larger pools, such as a 30-foot round pool, you will need to increase the amount of chlorine added, to 3 to 5 gallons per month.

Chlorine Demand
When determining how much liquid chlorine to add, you must also consider the chlorine demand of your pool. Chlorine demand is the amount of chlorine that is used up in a given period of time. This can be affected by factors such as the amount of sunlight the pool receives, the amount of swimmers in the pool, and the amount of debris in the pool. Generally, if the chlorine demand is high, you will need to add more chlorine than if the chlorine demand is low.
Testing the Chlorine Level
The best way to determine how much liquid chlorine to add to your pool is to test the chlorine level. This can be done using a chlorine test kit, which is available at most pool supply stores. The test kit contains test strips which you dip into your pool water and compare to the color chart on the box. The color chart will tell you how much free chlorine is in the pool. The free chlorine is the amount of chlorine that is available to sanitize the pool.
Adding Liquid Chlorine
Once you have tested the chlorine level, you can then determine how much liquid chlorine to add. Generally, you will want to maintain a free chlorine level of 1 to 3 parts per million (ppm). For a 20-foot round pool, you will need to add 1 to 1.5 gallons of liquid chlorine per month to maintain a healthy chlorine level. For a 30-foot round pool, you will need to add 3 to 5 gallons of liquid chlorine per month.

Conclusion
Adding chlorine to your pool is essential for keeping it safe and clean. Liquid chlorine is one of the most common forms of chlorine used to sanitize pools. The amount of liquid chlorine you add to your pool depends on the size of your pool and the amount of chlorine you need to maintain a healthy chlorine level. The best way to determine how much liquid chlorine to add is to test the chlorine level using a chlorine test kit. Generally, you will want to maintain a free chlorine level of 1 to 3 parts per million (ppm), adding 1 to 1.5 gallons of liquid chlorine per month for a 20-foot round pool, and 3 to 5 gallons of liquid chlorine per month for a 30-foot round pool.