The Three Types of Pool Algae and How to Get Rid of Each (The Right Way)
Is Your Pool Turning Green? Or Worse, Black? You're Not Alone.
Few things are more disheartening for a swimming pool owner than waking up to a pool that's anything but sparkling clear. Pool algae isn't just unsightly; it can make your water unsafe, clog your filter, and be a real headache to remove.
The key to successfully getting rid of algae is understanding what type you're dealing with. Not all algae are created equal, and what works for a mild case of green algae won't cut it for stubborn black algae.
As your trusted pool care experts, we're here to help you identify the enemy and arm you with the right solutions.
Why Does Pool Algae Form in the First Place?
Before we dive into the types, let's quickly understand the culprits:
Low Chlorine Levels: The most common reason. Insufficient pool sanitizer allows algae to take hold.
Poor Circulation/Filtration: Dead spots in your pool where water doesn't move are prime breeding grounds.
High Phosphates: Phosphates are a food source for algae.
Warm Temperatures: Algae thrives in warm, sunny conditions.
Improper pH: An unbalanced pool pH can reduce chlorine effectiveness.
The Three Main Types of Pool Algae: Identification & Treatment
1. Green Algae (Chlorophyta) – The Most Common Nuisance
Green algae is what most people picture when they think of an algae bloom.
Identification:
Water turns a cloudy green, ranging from light to dark.
Slimy feel on pool surfaces.
Can float in clumps or cling to walls and steps.
How to Get Rid of It:
Brush Vigorously: Scrub all pool surfaces, steps, and ladders to dislodge the algae.
Test & Balance: Ensure your pool pH is between 7.4−7.6.
Heavy Shock Treatment: Add a strong dose of pool shock (often 3-5 times the normal amount) to kill the algae. Follow product instructions carefully.
Run Filter Continuously: Keep your pool pump and filter running 24/7 until the water clears. Backwash or clean your filter frequently.
Add Algaecide (Optional but Recommended): A good quality algaecide can help prevent recurrence.
2. Yellow Algae (Mustard Algae / Phaeophyta) – The Stubborn Desert Dweller
Yellow algae is tougher to eradicate than green algae because it's chlorine-resistant and often hides in shaded areas or on pool toys.
Identification:
Appears as a powdery, yellowish-brown film.
Often found on pool walls, steps, and especially in shaded spots.
Can be brushed off easily but quickly reforms.
How to Get Rid of It:
Brush, Brush, Brush: Use a stiff-bristled brush aggressively.
Clean Everything: Algae spores can cling to anything! Clean pool filters, ladders, toys, and even swimsuits that have been in the pool.
Specialized Algaecide: Use an algaecide specifically formulated for yellow algae.
Triple Shock: This type requires a very heavy pool shocking – often 3-5 times the normal amount, sometimes even more.
Maintain High Chlorine: Keep your free chlorine levels higher than usual (3−5ppm) for several days after treatment.
3. Black Algae (Cyanobacteria) – The Unwelcome Guest
This is actually a form of cyanobacteria (blue-green algae) that forms a protective, multi-layered shield, making it incredibly difficult to remove.
Identification:
Small, dark black spots that cling tenaciously to pool walls, floor, and plaster.
Often feels crusty and is nearly impossible to brush off with a regular brush.
Usually found in rough surfaces or cracks.
How to Get Rid of It:
Aggressive Brushing: Use a stainless steel algae brush (for plaster pools) or a specialized brush (for vinyl/fiberglass) to physically break through its protective layers.
Chlorine Tablets Direct: Place an unwrapped chlorine tablet directly on the spots (for plaster pools only, and for short periods) to allow it to dissolve and penetrate. Use extreme caution and never let it sit too long.
Heavy Shock & Algaecide: A very strong pool shock combined with a specialized black algae algaecide is essential.
Repeat & Filter: This type of algae often requires repeated treatments and continuous filtration.
Clean Filter Aggressively: Black algae spores are tiny and will clog your filter.
Prevention is Always the Best Policy for a Clean Pool
Regular pool maintenance is your best defense against all types of algae:
Maintain Chemistry: Consistent pool water testing and balancing, especially chlorine levels.
Brush Regularly: Even a clean pool benefits from weekly brushing.
Run Your Filter: Ensure adequate circulation daily (8-12 hours, depending on size/use).
Clean Filters: Regularly backwash or clean your pool filter.
Address Phosphates: Consider a phosphate remover if you have recurring algae issues.
🛑 Algae Got You Down? Let the Professionals Handle It!
Dealing with pool algae outbreaks, especially yellow or black, can be exhausting and time-consuming. It often requires specific chemicals and a robust cleaning process to ensure it doesn't immediately return.
Don't spend another weekend scrubbing and stressing. As your local pool care service, we have the tools, expertise, and commercial-grade treatments to eliminate algae effectively and keep it from coming back.
Ready for an algae-free, sparkling pool? Contact us today for a consultation or to schedule professional algae removal! Call or text us at: 727-788-0864
