Black algae in pool water has always been one of the hardest problems for pool owners. You will see them a dark and tough spots on surfaces that are very hard to remove from the brush, and they can survive even after harsh chemical treatments.
Patience is the virtue if you really want to be free from them. With the help of the right tools and strategies and with our proper guidance, you will succeed. You will be able to make your pool safe again with the right chemical to kill black algae in pool.
What Is Black Algae in Pool
Don’t take black algae as an ordinary algae; it is actually a type of cyanobacteria that creates a tough layer around itself to protect itself from removal. It grows in plaster, tile grout, and concrete, so a simple brush cannot remove it. Sometimes people get confused with it for black spots in pool, not algae, but genuine black algae has a rough, slimy texture.
Common Signs You Have Black Algae
- Dark blue-green or black patches on pool walls or floors
- Spots that feel rough or gritty when touched
- Stains that resist normal brushing and don’t fade after shocking
- Spots reappearing even after cleaning
Where Black Algae Usually Grows
- Along shady walls and steps
- In the tile grout lines
- On rough or porous plaster
- Near poor water circulation areas
Difference Between Black Algae and Stains
- Black spots in pool not algae, are often mineral deposits or metal stains
- True black algae has a slimy feel and resists scrubbing
- Stains don’t usually spread, while algae can grow and multiply
what causes black algae in a swimming pool
Black algae (actually blue-green algae) forms in swimming pools due to poor water chemistry (low chlorine, high pH), inadequate circulation, and ineffective filtration. High levels of phosphates, organic debris like leaves, and rough pool surfaces also promote its growth. A lack of proper maintenance, including insufficient brushing and shocking, allows these resilient algae to thrive, especially in areas of poor circulation and sanitation.
Poor Circulation
- Dead spots where water doesn’t flow allow algae to grow
- Corners, steps, and behind ladders are prime areas
Contaminated Equipment
- Swimwear or toys used in lakes or oceans can carry black algae spores into your pool.
- Using uncleaned pool brushes from other pools can transfer algae.
Inconsistent Sanitation
- Low chlorine levels give black algae a chance to multiply
- Skipping regular shocking allows bacteria to thrive
How to Remove Black Algae from Pool Bottom
Black algae is one of the toughest pool problems because it forms a protective layer and roots deep into plaster or concrete. To remove it from the bottom of the pool you need a multi-step approach with the right products and tools.
Tools and Products You’ll Need
- Black algae pool brush with stainless steel bristles for hard scrubbing
- High-strength black algae pool chemicals (algaecide designed for black algae)
- Chlorine shock treatment
- Protective gloves and goggles
Step-by-Step Removal Process
- Step 1 – Brush Aggressively
- Use your black algae pool brush to break the algae’s protective layer
- Focus on affected spots, scrubbing until surfaces feel smoother
- Step 2 – Apply Targeted Algaecide
- Use a chemical to kill black algae in pool directly on scrubbed spots
- Follow the manufacturer’s safety instructions
- Step 3 – Super Chlorinate the Pool
- Shock your pool with 2–3 times the normal dose of chlorine
- Run the pump continuously for at least 24 hours
- Step 4 – Brush Again After 24 Hours
- Loosen any remaining roots
- Vacuum debris to waste to prevent recontamination
- Step 5 – Balance Your Pool Water
- Maintain chlorine at 3 to 5 ppm
- Keep pH between 7.2 and 7.4
Preventing Black Algae from Coming Back
- Brush and vacuum your pool weekly
- You must give shock treatment after rain or a storm.
- Swimsuits should be washed after use in lakes or oceans before entering the pool
- Keep your filtration system perfect and running continuously.
Tips for Stubborn Cases
- For removing black algae from pool walls, use a chlorine tablet to spot scrub affected areas
- In severe cases, a pool drain and acid wash may be necessary
- Consistent maintenance is the only long-term solution
Conclusion
The selection of the right tools and techniques is the key to success, whether it is a minor black algae attack or a hard one. The goal is to create a clean, safe, and enjoyable swimming environment for your loved ones. While these methods can help you tackle black algae yourself, having professional support ensures thorough and lasting results.
Aqua Pristine provides expert clean black algae pool services, maintenance, and repairs, so you can enjoy a safe and infection-free swimming experience.
Want to go beyond black algae? Check out our complete guide: [How to Get Rid of Algae in Pool Quickly with Home Remedies] — where we cover ways to spot, treat, and prevent all types of pool algae.
Areas We Serve
We proudly serve these locations in Florida:
- Fort Myers
- Cape Coral
- Estero
- Lehigh Acres
Ready to keep your pool crystal clear? Contact Aqua Pristine today for expert pool cleaning and maintenance services you can trust!
FAQs
1. How to get rid of black algae in pool?
You have to follow the treatment consistently to make it effective. First, scrub with a black algae pool brush, apply a strong algaecide, and run your pump continuously until the algae is gone.
2. Can you swim in a pool with black algae?
Black algae can carry many skin and eye irritation bacteria that can harm you, or you can become ill as well.
3. What to use for black algae in pool?
A chemical to kill black algae in pool and a brush specially designed for tough and rough surfaces.
4. What does black algae look like in a swimming pool?
It appears as dark black or blue-green spots that are rough to the touch and stubborn to scrub.
5. Why do I have black algae in my pool?
poor circulation, low sanitizer levels, or contaminated swimsuits or equipment can be the reasons for producing it.
6. Why does my pool have black algae?
There are many reasons to grow black algae. It grows in warm, still water. The pool has low chlorine levels. You will find it in cracks and on rough surfaces.
7. Can you pressure wash black algae in a pool?
Yes, but it can help only in drained pools, and it will not give you complete results. You will have to use chemicals to kill it from the root.
8. Is black algae in pool dangerous to humans?
Yes. it can be harmful because it can carry harmful bacteria that can cause irritation, rashes, and infections.
9. Will shock kill black algae in pool?
Only shock cannot do that alone; there has to be a combination of shock, brush, and use of algaecide.