How to get rid of black algae in the pool

Black algae in pools can be a stubborn and unsightly problem for pool owners. This resilient type of algae clings to pool surfaces, forms dark spots, and resists regular cleaning methods. Unlike other algae types, black algae have a protective outer layer, making it harder to remove. If left untreated, it can compromise water quality and even damage your pool’s surfaces. In this guide, we’ll walk you through how to get rid of black algae in the pool effectively and restore its sparkling appearance.

Step 1: Identify Black Algae

The first step in removing black algae is correctly identifying it. Black algae appear as dark, black or blue-green spots, primarily on rough pool surfaces like plaster or grout. Unlike other algae, black algae embed themselves deep into porous surfaces, making them tougher to eliminate. If you notice these spots, act quickly to prevent further spread.

Step 2: Gather Necessary Tools and Chemicals

To successfully remove black algae, you’ll need the right tools and chemicals. Here’s what you’ll need:

• Pool brush (preferably with stainless steel bristles for plaster surfaces)

• Chlorine tablets

• Algaecide (specifically designed for black algae)

• Shock treatment (calcium hypochlorite is effective)

• Pool water test kit

• Protective gloves and goggles

• Vacuum or pool cleaner

Step 3: Test and Balance the Water

Before treating the pool, test the water’s chemical levels using a pool water test kit. Ensure that pH levels are between 7.2 and 7.6, and maintain a chlorine level of 1-3 ppm. Balanced water enhances the effectiveness of chemicals and prevents the black algae from thriving.

Step 4: Brush the Affected Areas

Use a pool brush with stiff bristles to scrub the affected areas thoroughly. Focus on the dark spots where black algae are present. Brushing helps break the algae’s protective outer layer, allowing the chemicals to penetrate and kill it. Be persistent, as black algae grip tightly to surfaces.

Step 5: Apply Chlorine Tablets Directly

After brushing, apply a chlorine tablet directly to the affected spots. Hold the tablet against the algae for a few minutes to deliver a concentrated dose of chlorine. This method is particularly effective for killing the deep-rooted black algae colonies.

Step 6: Shock the Pool

Perform a shock treatment to raise the chlorine level and kill any remaining algae spores in the water. Use a shock treatment specifically designed for swimming pools, following the manufacturer’s instructions. For severe black algae infestations, you may need to double or triple the usual shock dosage.

Step 7: Use an Algaecide

Once the shock treatment is complete, add a black algae-specific algaecide to the water. Algaecide serves as an additional line of defense by targeting any lingering algae. Ensure proper circulation of water by running the pool pump for at least 24 hours to distribute the algaecide evenly.

Step 8: Vacuum and Filter the Pool

After the chemicals have worked their magic, vacuum the pool to remove dead algae and debris. Clean or backwash your pool filter to prevent reintroduction of algae spores. For pools with cartridge filters, rinse or replace the cartridge as necessary.

Step 9: Monitor and Maintain

Black algae can reappear if the pool is not properly maintained. Regularly test and balance the water’s chemical levels to prevent algae growth. Brush the pool surfaces weekly and run the pump daily to ensure adequate circulation. Investing in a robotic pool cleaner can also help keep surfaces clean and algae-free.

Preventing Black Algae in the Future

Prevention is key to avoiding future outbreaks of black algae. Here are some tips:

1. Maintain proper water chemistry: Regularly test and adjust the pH, chlorine, and alkalinity levels.

2. Brush and clean the pool: Regular brushing prevents algae from taking hold on surfaces.

3. Use a pool cover: Covering the pool reduces sunlight exposure, which algae need to grow.

4. Shower before swimming: Encourage swimmers to rinse off before entering the pool to reduce contaminants.

5. Run the pump and filter regularly: Good circulation prevents stagnant water where algae can thrive.

Final thought

By following these steps and maintaining your pool properly, you’ll be able to keep black algae at bay and enjoy a clean, inviting swimming pool. Now that you know how to get rid of black algae in the pool, you’re equipped to tackle this issue head-on and maintain a pristine pool all season long.