Why Algae Forms On Pool Decks (And How To Remove It)
Algae on pool decks is more than just slippery and ugly. This guide explains why it happens and gives you the tools to clean and stop it for good.
You walk out to your pool expecting a relaxing day, only to slip on a slick, green patch on your deck. Algae has crept in again. It looks gross, feels slimy, and can even be dangerous. But what causes algae to grow on your deck in the first place?
Pool deck algae is common, especially in warm, humid climates. But with the right maintenance, cleaning schedule, and a few good habits, you can keep it under control.
What Causes Algae On Pool Decks?
Algae needs three things to thrive: moisture, warmth, and organic material. Your pool deck is often exposed to all three.
Key Triggers Include:
- Frequent splashing or rainwater buildup
- Poor drainage around the deck
- Shade from trees or structures
- Dirt, leaves, or organic debris
- High humidity and warm temperatures
Even if your pool is perfectly balanced, the surrounding area can still grow algae if these conditions are not addressed.
Where Does It Usually Grow?
Algae loves corners, shaded areas, and textured surfaces. Common problem spots include:
- Under patio furniture
- Along expansion joints
- Cracks in concrete or tile
- Between pavers
- Behind planters or decorations
If water tends to sit in one spot, algae will find it.
How To Remove Algae From Pool Decks
Step 1: Sweep Or Blow Off Loose Debris
Use a broom or leaf blower to remove leaves, dirt, and loose debris. This prevents organic matter from feeding the algae further.
Step 2: Scrub With A Cleaning Solution
Mix one of the following:
- 1 part bleach to 10 parts water
- A commercial outdoor algae remover
- 1 cup white vinegar to 1 gallon water (for mild cases)
Use a stiff-bristle brush or deck scrubber. Scrub affected areas thoroughly.
Step 3: Rinse With A Hose Or Pressure Washer
Use a hose with a strong spray setting or a pressure washer for deeper cleaning. Make sure to rinse away all residue.
Step 4: Let It Dry Completely
Algae cannot survive dry surfaces. Let your deck dry fully before allowing foot traffic or putting furniture back.
How To Prevent Algae From Returning
1. Improve Drainage
Standing water is the number one cause of algae. Fix low spots and make sure your deck slopes away from the pool.
2. Keep It Clean Weekly
- Sweep off debris regularly
- Hose down the deck after parties or stormy days
- Scrub trouble spots as needed
3. Apply A Sealant
Deck sealants create a water-resistant barrier. Choose one rated for mold and algae resistance.
4. Use A Mold And Algae Inhibitor
Some products can be sprayed on clean surfaces to prevent future growth.
5. Trim Back Plants
Too much shade keeps areas wet longer. Trim trees and bushes to increase sunlight and airflow.
When To Call A Professional
If your deck has deep cracks, layers of old algae, or needs heavy pressure washing, consider hiring a pro. They can restore concrete, reseal surfaces, and offer long-term solutions.
Quick Algae-Fighting Checklist
- Sweep off debris 2 to 3 times a week
- Rinse the deck after pool use
- Scrub with a bleach solution monthly
- Improve drainage and airflow
- Use deck sealant once a year
Moral: If you keep your deck dry, clean, and in the sun, algae will have no chance to settle in. Stay one step ahead, and your pool area stays safe and slip-free.