How to lower high pH in a pool without chemicals

Understanding pH Levels in Your Pool

Maintaining the right pH balance in your pool is crucial for keeping the water safe and comfortable for swimming. Here in New Zealand, our weather conditions and water sources can sometimes cause pH levels to rise, leading to issues like cloudy water, skin irritation, and reduced effectiveness of pool sanitiser. While many pool owners turn to chemicals like muriatic acid to lower pH, there are natural methods you can use that are both effective and environmentally friendly.

Why Does pH Rise in a Pool?

Before we dive into solutions, it’s helpful to understand why pH levels increase in the first place. Some common reasons include:

High alkalinity – If your pool’s total alkalinity (TA) is high, it will naturally cause the pH to rise.
Aeration – If you have water features like fountains or aerators, they can introduce oxygen that raises pH levels.
Local water supply – The water in some areas of New Zealand, particularly regions with hard water, tends to have a naturally high pH.
Swimming activity – Heavy pool use, especially splashing and introducing organic materials like sweat or sunscreen, can contribute to pH fluctuations.

Reducing pH Naturally

If you prefer to avoid store-bought chemicals, there are a few alternative methods to help lower your pool’s pH naturally.

1. Use Rainwater

Rainwater is naturally acidic (typically around a pH of 5.0-5.5), making it a great way to naturally lower the pH in your pool. If you’re expecting rain, you can:

Allow rain to fill part of your pool instead of topping it up with tap water.
Collect and store rainwater in a tank, then add small amounts to help balance out pH levels.

Tip: Check your area’s rainfall forecast using MetService (www.metservice.com) to plan when to collect water.

2. Increase Aeration

While aeration can raise pH over time, when combined with lowering alkalinity, it can help stabilise the pool’s balance. To do this naturally:

Reduce total alkalinity using rainwater or through dilution.
Use aeration (such as waterfalls, fountains, or spa jets) to slowly stabilise pH levels.

3. Add Organic Matter

Some organic materials, like peat moss, can help lower pH in a controlled way. This method is used in natural pools and aquariums, and some Kiwi pool owners have experimented successfully with:

Peat Moss – Place a small mesh bag filled with peat in your pool skimmer or directly in the water. This will slowly release tannins that naturally lower pH.
Driftwood – While more commonly used in aquariums, certain types of driftwood can release mild acids into the water.

Note: These methods work gradually and require monitoring.

4. Dilution with Lower-pH Water

If your pool’s pH is continually high, consider dilution with water that has a lower pH. You can:

Partially drain the pool and refill with a water source that has a naturally lower pH.
Use collected rainwater (as mentioned earlier) to dilute high-pH water in small increments.

Before doing this, it helps to test both your pool water and your refill source. You can find water test kits at Kiwi-owned retailers like Para Rubber (www.pararubber.co.nz) or Pool & Spa Warehouse (www.poolandspa.co.nz).

Keeping Your Pool’s pH Stable

Lowering your pH is only half the challenge—keeping it stable is the key to long-term maintenance. To prevent future issues:

Test your water regularly – Invest in a reliable test kit from local suppliers like Clark Rubber NZ (www.clarkrubber.co.nz).
Balance alkalinity properly – Keeping total alkalinity in check (between 80-120 ppm) makes it easier to maintain correct pH levels.
Monitor weather conditions – Warmer temperatures and lots of swimmers can cause fluctuations. Adjust accordingly.

Final Thoughts

Keeping a pool’s pH balanced without chemicals takes a bit of effort, but it’s doable with the right approach. By utilising natural methods like rainwater, aeration, and organic materials, you can create a healthier, more eco-friendly swimming environment.

Have you tried any of these methods in your own pool? Let us know your experiences and any other natural remedies you’ve found helpful!

Pool Owners New Zealand