Algae in your pool? Annoying, right? It turns the water green, makes surfaces slippery, and just ruins the whole swimming experience. Most people dump a bunch of chemicals in, but if you’re looking for a natural approach, there are definitely ways to clear your pool without relying on chlorine or algaecide. Let’s get into it.

Get That Filter Running—A Lot

Algae thrives in still water. If your pool pump hasn’t been running enough, that’s part of the problem. Turn up the filtration. Instead of the usual 6–8 hours a day, try running your pump continuously until the water clears. The more moving water, the harder it is for algae to stick around.

By the way, check the filter while you’re at it. If it’s clogged or dirty, it won’t be doing much to help. Give it a proper clean or backwash if needed—especially if you’ve got a sand filter.

Brush, Brush, Brush

Algae loves clinging to pool walls, steps, and floors. Just leaving it there won’t help. Grab a stiff pool brush and scrub all surfaces hard. This breaks up the algae and makes it easier for your filter to trap it.

Vinyl or fibreglass pool? Use a softer brush to avoid damage. Concrete pools can handle more aggressive brushing.

Try a Pool Vacuum (But Not Just Any)

Once you’ve scrubbed all that algae loose, you need to remove it. A regular pool vacuum can help, but if you’ve got a serious algae bloom, a manual vacuum set to “waste” mode is your best bet. That way, the contaminated water goes straight out of the pool instead of cycling back through the filter.

If you don’t have one, check out places like Bunnings NZ, Mitre 10, or Pool & Spa Warehouse NZ—they should have pool vacuums that can do the job.

Use a UV or Ozone System

If you want a more long-term, chemical-free solution, UV and ozone systems kill bacteria and algae without adding anything to the water. They’re becoming more popular in NZ, especially for eco-friendly pool maintenance. Ask your local pool supply store (like Maytronics NZ) if they have options that fit your setup.

Add Baking Soda or Salt

Baking soda can help with scrubbing and balancing pH, but it’s not a direct algae killer. However, if you’ve got a saltwater pool, increasing the salt levels slightly can naturally prevent algae from coming back.

Some Kiwis also swear by barley straw—yep, regular barley straw bundles—but that’s more for ponds than pools.

Solar Covers—A Hidden Problem

Have a pool cover? Algae loves the warmth and light trapped under it. If you’re dealing with an outbreak, keep the cover off for a while and let the water breathe. Heat combined with stagnant water is a paradise for algae.

Prevent It from Coming Back

Once you’ve got the algae out, you want to keep it out. Here’s what helps:

• Keep the filter running daily (aim for at least 8 hours in summer).
• Regular brushing and vacuuming—even when the water looks clear.
• Check pH and water balance—too much acidity or alkalinity makes it easier for algae to thrive. You can grab a basic water test kit from Placemakers or your local hardware store.
• Avoid overloading your pool with organic stuff—leaves, bird droppings, sunscreen… all these feed algae. Skim your pool regularly.

When It’s Really Bad

Sometimes, if the algae problem is huge, the natural methods might take too long or not work fast enough. If you’ve tried everything and it’s still a swamp, you might need to use a pinch of chemicals—just enough to clear it up, then switch back to natural maintenance.

Final Thoughts

Removing algae without chemicals takes effort, but it’s 100% doable. Keep the water moving, scrub your pool, and stay on top of maintenance. Once you’ve got a good routine down, it’ll be much harder for algae to take over in the first place.

Good luck—and happy swimming!