How Much Algaecide Should I Add to My Pool?

. Dosage Based on Treatment Timing

1. Initial Dosage

When using algaecide for the first time or after a long period without treatment, you will need an initial “shock” dose. This larger dose helps to quickly establish control over algae and prepare the pool for regular maintenance. Typically, the initial dosage for many algaecides is about 16 ounces (1 pint) per 10,000 gallons of water. Check the specific product instructions for exact amounts.

2. Regular Maintenance Dosage

For ongoing maintenance, a smaller, regular dose is required to keep algae at bay. This ensures that the pool remains algae-free over time without the need for drastic measures. Generally, a maintenance dose might be around 4 ounces (1/4 pint) per 10,000 gallons of water weekly. Regularly applying this dose helps to prevent algae from growing and keeps your pool water clear.

3. Dosage During Algae Outbreaks

When facing an algae outbreak, a higher dose may be necessary to quickly regain control. This intensified treatment helps to eliminate the algae quickly and effectively. For severe outbreaks, follow the product’s specific recommendations, which might suggest doubling the initial shock dose. For instance, you might need up to 32 ounces (2 pints) per 10,000 gallons of water to combat a significant algae bloom.

. Specific Product Examples

Different types of algaecides have varying dosage recommendations. Here are some general guidelines for the most common types of algaecides:

1. Copper-based Algaecide

Initial Dose: 16 ounces per 10,000 gallons

Maintenance Dose: 4 ounces per 10,000 gallons weekly

Outbreak Dose: Follow product instructions, usually higher than the initial dose.

2. Quat (Quaternary Ammonium) Algaecides

Initial Dose: 12-24 ounces per 10,000 gallons

Maintenance Dose: 4-8 ounces per 10,000 gallons weekly

Outbreak Dose: Refer to the product’s specific instructions.

3. Polyquat Algaecides

Initial Dose: 8-12 ounces per 10,000 gallons

Maintenance Dose: 3-6 ounces per 10,000 gallons weekly

Outbreak Dose: Consult the product label for exact recommendations.

4. Natural Algaecides

Initial Dose: Typically more generous amounts initially as per the product guidelines.

Maintenance Dose: Small, regular doses based on the product instructions.

Outbreak Dose: Refer to product-specific guidelines.

. Calculating Pool Volume

If you don’t know your pool’s volume, you can calculate it using the following formulas:

Rectangular Pool: Length (ft) × Width (ft) × Average Depth (ft) × 7.5 = Total Gallons

Round Pool: Diameter (ft) × Diameter (ft) × Average Depth (ft) × 5.9 = Total Gallons

Oval Pool: Length (ft) × Width (ft) × Average Depth (ft) × 6.7 = Total Gallons

. Example Calculation:

Let’s say you have a rectangular pool that is 20 feet long, 10 feet wide, and has an average depth of 5 feet. Using the formula for a rectangular pool:


This means your pool holds 7,500 gallons of water.

. Tips for Adding Algaecide

1. Distribute Evenly

Pour the algaecide around the perimeter of the pool to ensure even distribution. This helps the algaecide to reach all areas of the pool effectively.


2. Run the Filter

After adding the algaecide, run your pool’s filtration system for at least 24 hours. This helps circulate the algaecide throughout the pool, ensuring it reaches every corner and kills the algae.

3. Regular Maintenance

Stick to a regular maintenance schedule to prevent algae from gaining a foothold. Regularly test your water chemistry to keep it balanced. Consistent maintenance makes it easier to control algae with minimal effort.

4. Safety First

Always wear gloves and eye protection when handling pool chemicals. Read the safety instructions on the algaecide bottle and store chemicals safely out of reach of children and pets.