🟢 How to Fix a Green Pool: Step-by-Step Guide

The following is general advice only. Requirements for individual pools and pool systems may vary.

A green pool is every pool owner's nightmare—especially when it happens right before the weekend or a heatwave! That green tinge usually means algae has taken over, and it’s more than just unsightly—it can pose health risks and damage your pool equipment if left untreated.

But the good news? You can restore your pool to crystal clear with the right tools, treatment, and a little elbow grease.

Here’s your step-by-step guide to turning your green pool sparkling blue again.

✅ Step 1: Identify How Green Your Pool Is

Not all green pools are the same. The colour can tell you how far along the algae bloom is:

  • Light green – Early-stage algae; water still somewhat transparent

  • Dark green/black – Advanced bloom; water is murky and potentially dangerous

  • Milky green – Often means dead algae particles suspended in the water

The darker the green, the more work is required.

🧽 Step 2: Clean the Pool

Before you shock the water, remove as much debris as possible. This reduces the organic matter that feeds algae and helps your chemicals work more effectively.

  • Skim leaves and floating debris

  • Brush the walls and floor thoroughly to loosen algae

  • Vacuum if visibility allows (use waste mode if you have a multiport valve)

⚖️ Step 3: Test & Balance the Water

Use a reliable pool water test kit or bring a sample into WaterPro Pool and Spa for analysis. Check:

  • pH – Aim for 7.2–7.4 before shocking

  • Alkalinity – 80–120 ppm

  • Chlorine – Likely near zero if the pool is green

Important: If the pH is too high, chlorine becomes less effective. Use pH reducer (acid) to bring it into the correct range before treatment.

💥 Step 4: Shock the Pool

Time to kill the algae!

  • For mild algae: Use 2–3 times the normal chlorine dose

  • For dark green pools: Use 4–5 times the normal dose

Use either:

  • Calcium Hypochlorite

  • Liquid chlorine

  • Other specialty shock-specific products - ask in-store

Pro tip: Shock the pool in the evening to prevent UV degradation and let it work overnight.

🌪 Step 5: Circulate, Brush, and Filter

Run your pump and filter continuously for 24–48 hours. Backwash your sand filter or clean your cartridge as needed—often several times during this process.

Brush the pool daily to disrupt any remaining algae and help circulation.

🧼 Step 6: Use an Algaecide (Optional but Helpful)

After shocking, you can add a non-copper-based algaecide to prevent future outbreaks and help clear up stubborn patches.

Choose one that’s compatible with your pool type (e.g. salt, chlorine, etc.).

💧 Step 7: Floc or Clarify (If Water Is Cloudy)

If your pool is blue but cloudy, use a clarifier or flocculant to bind fine particles together so your filter can remove them more effectively.

  • Clarifier: Helps your filter trap particles

  • Flocculant: Drops everything to the bottom so you can vacuum to waste

📅 Step 8: Retest, Balance, and Maintain

Once the water is clear:

  • Recheck your pH, alkalinity, and chlorine

  • Adjust as necessary

  • Resume regular maintenance (chlorine, brushing, filtration)

🛠 Need Help? We’ve Got You Covered

If you're dealing with a green pool, visit our store for:

  • Professional water testing

  • Expert advice

  • Pool shock, algaecides, clarifiers, brushes, vacuums, and more

We’ll help you choose the right products for your pool and walk you through each step.

Don’t let algae ruin your summer. A green pool is a temporary setback, and with the right approach, you’ll have it sparkling again in no time.

Drop into WaterPro Pool and Spa (2/439 Gympie Road, Kedron), give us a call (1300 447 665), or contact us. Our friendly team is here to help you keep your pool sparkling, balanced, and ready to dive into!