If your pool water’s starting to sting your eyes, scale up your pipes, or just looks a bit cloudy—it could be your pH and alkalinity are out of whack. The good news? You don’t always need to dump a bunch of chemicals in to fix it. There are natural ways to get things back in balance. Let’s walk through it, Kiwi style.

First up, here’s what matters…

pH basically tells you how acidic or basic your pool water is. You want it between 7.2 to 7.6—this is the sweet spot where chlorine works best and your skin doesn’t turn into sandpaper. Alkalinity? That’s like the buffer that keeps your pH from bouncing around. Aim for somewhere between 80 to 120 ppm (parts per million). Too low and things get acidic fast. Too high and your pH goes stubborn like a teenager.

Start with a proper test

Before you do anything else, test your water. No point guessing. You can grab a test kit from your local Mitre 10 or Bunnings here in NZ. They’ve got the strips or liquid kits—either one’ll do fine. Test in the morning before the sun’s had a chance to mess with your readings.

So, if your results show low pH and alkalinity…

Start with baking soda – yep, the stuff from your pantry

Think of baking soda like first aid for pool water. It’s perfect for raising alkalinity without throwing your pH way out of balance. If your alkalinity is low (below 80 ppm), this is what you should do:

• Measure out about 1 tablespoon of baking soda per 4,000 litres of water to raise total alkalinity by around 10 ppm.
• Sprinkle it across the surface—don’t dump it all in one spot—while your pool’s pump is running.
• Give it a few hours, then test again before adding more.

A typical Kiwi backyard pool holds anywhere from 20,000 to 50,000 litres, so adjust accordingly. Countdown or New World will have baking soda in big bags in the baking aisle that’ll do the trick.

Now if your pH is too low, but your alkalinity’s fine…

Try soda ash (sodium carbonate)

This raises pH quickly without moving alkalinity too much. Use it carefully—too much and things can go the other way. Look for it at local pool stores like Pool & Spa 2Go or Paramount Pools. Some even do bulk packs and delivery if you’re out rural.

What if alkalinity’s too high?

Here’s where it gets a bit more hands-on. High alkalinity makes pH hard to adjust—like trying to steer a waka uphill. If you’re pushing 150 ppm on the test kit, this is what you should try:

• Use plain white vinegar or citric acid (AsureQuality reckons both are food-safe and safe for home use). These are natural acids that bring down alkalinity slowly and help nudge the pH back to normal.
• Add a bit at a time, with your filter running, and test every hour or two.
• Be patient. Don’t dump in a bottle and expect miracles.

Don’t forget aeration

If you’re using something acidic to lower alkalinity, the pH might dip a bit too low. The trick to bringing the pH back up naturally, without chemicals? Add air.

It’s kind of like when you blow into chocolate milk with a straw and it fizzes up—more bubbles equals higher pH. Here’s what you can do:

• Point your return jets upwards
• Turn on a water feature (if you have one)
• Use a pool fountain (easy to attach to most return pipes)

All this adds air to the water and nudges the pH up while alkalinity stays put. It’s slow, yeah—but it works.

Be consistent with maintenance

Once you’ve got your pH and alkalinity in the right range, keep an eye on it each week. Don’t wait until someone complains about itchy eyes. Make testing a weekend habit—like mowing the lawns or checking the barbie gas.

You can also go semi-natural with maintenance. Some Kiwis swear by using a couple of tennis balls floating in the skimmer to soak up oils and keep things balanced. You won’t find that in every pool manual, but it’s a classic at the marae pool.

Where to get more help?

If you’re getting stuck or just want a second opinion, check out:

• Pool & Spa 2Go – they’ve got heaps of NZ-specific advice and kits.
• The Pool Place (Nationwide) – their team can test your water if you bring in a sample.
• Trade Tested – good for natural pool products and eco-friendly filters.
• Stuff.co.nz also has a few ‘Kiwi summer’ guides on pool care from real backyard users.

Anyway, there you have it.

Balancing pH and alkalinity naturally isn’t rocket science—it’s more like baking a cake. Get the ingredients right, go one step at a time, and you’ll have clear, comfy water without turning your pool into a chemical soup.

Keep it simple, stay consistent, and don’t forget—your pool should feel like a mini-holiday, not a constant headache.