How Much Algaecide to Put in Pool?

When dealing with a troublesome algae bloom in your pool, it’s crucial to know how to properly use algaecide. But a question that often pops up is, how much algaecide should you put in your pool? Let’s dive into this topic to clarify things.

Understanding Algaecide

 What is Algaecide?

Algaecide is a chemical treatment specifically designed to kill and prevent algae in pools and spas. They come in liquid form and are directly added to the pool water to combat different types of algae such as green, yellow, and black algae.

Why Use Algaecide?

Algae can cause several problems. Not only can it make your pool look uninviting, but it can also clog filters and create slippery surfaces, increasing the risk of accidents. Algaecides are a vital tool in maintaining a clean, safe swimming environment.

Calculating the Right Algaecide Quantity

Determining the correct quantity of algaecide depends on three key factors: pool size, algae severity, and algaecide concentration.

Pool Size

The size of your pool directly impacts the amount of algaecide you’ll need. Larger pools will naturally require more algaecide than smaller ones. Pool sizes are typically measured in gallons, and you can find this information in your pool’s manual or by doing a simple calculation.

Algae Severity

The severity of the algae problem will also affect the algaecide quantity. More severe infestations may require a larger dose of algaecide.

Algaecide Concentration

Lastly, different algaecides come in different concentrations. Always check the product label for dosage instructions, as the concentration will affect how much you need to use.

Step-by-Step Guide to Applying Algaecide

Step 1: Testing Pool Water

First, test your pool water to determine the pH level and the severity of the algae problem. Adjust the pH level to around 7.2-7.6 if necessary, as algaecides work best in this range.

Calculating Algaecide Amount

Use the algaecide instructions, your pool size, and the severity of the algae problem to calculate the necessary algaecide amount.

Step 3: Applying Algaecide

Pour the algaecide evenly around the edges of the pool, then let the pool pump run for at least 8-10 hours to circulate the algaecide evenly. Avoid swimming until the algaecide has had time to work, typically 24 hours.

Algaecide Safety and Precautions

Safe Storage

Algaecide is a chemical, and as such, it should be stored in a cool, dry place, away from children and pets. Ensure the container is tightly sealed to prevent any accidental spillage.

Application Precautions

Always wear protective clothing, including gloves and goggles, when handling algaecide. Don’t overdose your pool with algaecide, as it can lead to foamy or cloudy water and may irritate swimmers’ skin and eyes.

Algaecide Alternatives

Physical Cleaning

Physical cleaning, such as scrubbing pool walls and vacuuming, can also help control algae growth. However, this method is labor-intensive and often used in conjunction with chemical treatments.

Saltwater Chlorinators

Saltwater chlorinators convert salt into chlorine, keeping your pool clean without the need for manual chlorine or algaecide addition. It’s a more natural method and less harsh on the skin and eyes.

ALSO SEE: How Long After Adding Algaecide Can You Shock?


Knowing how much algaecide to put in your pool is critical for maintaining a clean, safe swimming environment. Remember, the quantity of algaecide depends on your pool size, the severity of the algae, and the algaecide concentration. Always follow the manufacturer’s instructions and take necessary safety precautions when handling algaecide. If you’re looking for alternatives, physical cleaning and saltwater chlorinators can also be effective.


  1. How often should I put algaecide in my pool?

For regular maintenance, it’s typically recommended to add algaecide once a week. However, if you have a severe algae problem, you may need to treat the pool more often.

  1. Can you put too much algaecide in a pool?

Yes, adding too much algaecide can lead to foamy or cloudy water and may irritate swimmers’ skin and eyes. Always follow the manufacturer’s recommended dosage.

  1. Is algaecide harmful to humans?

In general, algaecide is safe for humans when used correctly. However, direct contact or ingestion can be harmful, so always handle with care.

  1. Can I swim immediately after adding algaecide?

It’s recommended to wait at least 24 hours after adding algaecide before swimming. This allows the algaecide time to effectively kill the algae.

  1. Are there natural alternatives to algaecide?

Yes, physical cleaning and saltwater chlorinators are alternatives to using algaecide. However, these methods may require more effort or investment.

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