- Categories: Pool Cleaning
How to Clean a Green Pool Fast and Safely: A Complete Guide
There’s nothing worse than pulling back the pool cover and discovering murky green water instead of a sparkling oasis. If your swimming pool has gone green, don’t panic. With the right tools and approach, you can restore it quickly and safely.
In this guide, we’ll walk you through how to clean a green swimming pool from start to finish. You’ll also learn how to stop algae from returning, so you can enjoy your pool all season long.
Signs Your Pool Is Going Green and Why
That green tinge in your water isn’t just ugly – it’s a warning sign that algae has taken over. Left untreated, it can become a breeding ground for bacteria and a serious headache for pool owners.
Early signs of algae in your pool:
• Water starts to look slightly green or cloudy
• Pool surfaces feel slippery or slimy
• There’s an increase in chlorine demand
• Your pool has a stale or musty smell
Why does this happen?
- Low chlorine levels – not enough sanitiser lets algae grow freely
- Unbalanced water – especially high pH or low alkalinity
- Poor circulation or filtration – stagnant water is algae’s best friend
- Hot weather – New Zealand summers are perfect for algae to bloom
- Organic debris – leaves, pollen, or dirt add fuel to the fire
Step-by-Step Process for Cleaning a Green Pool
Restoring your pool from green to clean isn’t complicated, but it does require a targeted approach. Here are eight steps on how to do it fast and safely.
1. Test the water first
Use a pool test kit to check: chlorine, pH and total alkalinity. In green pool cases, the pH is usually too high. Bring it down to 7.2 to help chlorine work better. You can use a pH decreaser like sodium bisulphate for this step.
2. Clear out debris
Use a skimmer or leaf net to remove as much surface debris as possible. Then vacuum the bottom of the pool thoroughly. The less organic material in the water, the more effective your chemicals will be.
3. Shock your pool with chlorine
This is the most important step in cleaning a green pool. Add a large dose of chlorine – around 3 to 5 times your normal amount – using a liquid or granular form. For fast results, use high-quality shock treatment like that in our pool chlorine range. Keep your pump running 24 to 48 hours to circulate the treatment fully.
4. Add algaecide
Once you’ve shocked the pool, follow up with an algaecide. Choose one that targets green algae specifically. This helps stop the regrowth of stubborn spores that survived the shock treatment.
5. Brush the walls and floor
Algae clings to surfaces, especially in corners and around steps. Use a stiff pool brush to scrub everything thoroughly. This helps dislodge any biofilm and ensures your chemicals reach all areas.
6. Filter continuously and backwash
Let your pump and filter run continuously during this process. Clean or backwash your filter regularly – it will be working hard to remove dead algae and particles.
7. Use a clarifier if needed
If your water is still cloudy after cleaning and filtration, add a pool clarifier. It helps bind fine particles so your filter can remove them more easily.
8. Re-test and balance the water
Once your water clears up, re-test everything and adjust as needed:
- Chlorine: 1.0 to 3.0 ppm
- pH: 7.2 to 7.6
- Total alkalinity: 80 to 120 ppm
- Calcium hardness: 200 to 400 ppm (especially important in N
Tips to Prevent Algae from Returning
Mastering swimming pool cleaning chemicals isn’t rocket science, but it does require consistency and quality products. The difference between a mediocre pool and a spectacular one often comes down to using premium pool chemicals and maintaining proper balance.
Stick to a regular maintenance routine
Once your water clears up, re-test everything and adjust as needed:
- Test water 2 to 3 times per week in summer
- Add chlorine consistently – don’t wait until it drops too low
- Keep your pH and alkalinity balanced
- Clean filters regularly and ensure good circulation
Use stabilised chlorine
Sunlight breaks down chlorine quickly, especially during peak summer. A stabilised chlorine product can help protect your sanitiser levels from UV rays.
Shock weekly during summer
Heavy use, high heat, or rainstorms can all reduce your chlorine’s effectiveness. A weekly shock treatment keeps things in check.
Remove organic matter fast
Leaves, bugs, pollen and dirt feed algae. Skim and vacuum regularly – especially after windy days or storms.
Ready to turn your green pool crystal clear?
Our expert team at Dolphin Pacific knows how quickly algae can take over – and how to stop it fast. From powerful shock treatments to stabilised chlorine and algaecides, we have everything you need to get your pool back on track. Explore our proven green-to-clean solutions today and see why we’re New Zealand’s go-to name in pool care.
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Hey! I'm Adrian, founder and pool expert here at Dolphin Pacific. I love spending time with family, fishing, and have been known to brew my own beer.
