So, your pool’s turned into a green swamp, and you’re wondering what to do. Don’t stress—it happens to almost everyone at some point. Whether it’s a bit cloudy or full-on algae central, the good news is that you can fix it. Here’s what you need to know and do to get your pool back to clear, sparkling water.

Why Your Pool Went Green

First things first—why did this even happen? The usual suspects are:

• Not enough chlorine – This is the big one. Without chlorine killing algae, they move in fast.
• Poor circulation – If your pump or filter isn’t running properly, algae and bacteria start partying.
• Imbalanced water – High pH or phosphates? That’s like giving food to the algae.
• Too much debris – Leaves, dirt, or bugs hanging out in the pool? They break down and feed algae.

Alright, let’s sort this out.

Step 1: Get Rid of Debris

Skim the pool and scoop out anything floating around—leaves, bugs, all of it. If there’s a lot on the bottom, use a vacuum. No point adding chemicals if there’s gunk feeding the algae.

Step 2: Check and Balance Your Water

Time to test the water. You’ll want a test kit or strips (you can grab these from places like Pools & Spas New Zealand or your local Mitre 10). Check for:

• Chlorine levels – If it’s low, that’s your problem.
• pH level – Needs to be between 7.2 – 7.6. Too high? Add acid. Too low? Add soda ash.
• Alkalinity – Should be between 80 – 120 ppm for everything to work properly.

Step 3: Hit It With Shock Treatment

Basically, you’re dropping a heap of chlorine in to kill the algae. You’ll need pool shock (sometimes called ‘chlorine shock’). You can grab it from Bunnings NZ or a specialist store like The Pool Warehouse.

Follow the dosage directions (usually 1-2kg per 50,000L depending on how bad it is). Pour it in at night so the sun doesn’t burn it off too quickly. Let the pump run overnight to circulate everything.

Step 4: Brush and Run the Filter

Once the chlorine gets to work, you’ll end up with dead algae sitting in the water. Brush the walls and floor thoroughly, then keep your pump running for at least 24 hours to filter everything out.

If your pool’s still cloudy, use a clarifier to help clear it up faster.

Step 5: Keep It Clean Going Forward

Now that your pool is back to normal, here’s how to stop it from happening again:

• Run your pump daily – At least 8 hours a day in summer, especially after heavy rain.
• Test your water weekly – Grab a kit and keep an eye on chlorine, pH, and alkalinity.
• Shock the pool regularly – At least every 2 weeks in summer to stay ahead of algae.
• Keep debris out – A pool cover helps, or just skim it daily if you’re using it often.

Bonus Tip: Use the Right Chemicals

New Zealand’s weather and water conditions can be unpredictable, so what works overseas might not be best here. Stick with trusted NZ brands like BioGuard, Zodiac, or HTH, which you can find at Swimple Pools or your local swim shop.

That’s it—no more green pool! It’s all about staying on top of maintenance. A few minutes a week checking chlorine levels and cleaning up makes a huge difference. Stay on top of it, and you won’t have to deal with another swamp situation anytime soon. Happy swimming!