What Should I Do If My Alkalinity Is Naturally High?

If you’ve tested your spa water and found the alkalinity is consistently high—even after refilling—it’s likely due to your local water source. Some regions have hard water or mineral-rich supplies that naturally raise the alkalinity level. While this isn’t uncommon, it does make hot tub care a little more hands-on.

Why High Alkalinity Is a Problem:

• Locks your pH in the wrong range

• Causes cloudy water and scale build-up

• Reduces the effectiveness of sanitisers

• Can lead to skin or eye irritation

  
  

How to Lower It:

1. Use an alkalinity reducer – Add small, measured doses of a product specifically designed to lower total alkalinity. Spa Fuel’s pH Reducer (which also affects alkalinity) can help—just follow the instructions carefully.

2. Circulate the water – Run your jets to help distribute the chemical evenly.

3. Test and repeat – Wait a few hours after each adjustment before retesting. It may take several rounds to bring it down into the ideal range (80–120 ppm).

4. Balance pH afterwards – Lowering alkalinity may also drop your pH below the ideal level. If needed, bring the pH back up using a small amount of pH Increaser.

   
   

Spa Fuel PRO Tip:

Always test alkalinity before adjusting pH, as it stabilises the water. Use your LaMotte test strips, and match the result to Spa Fuel’s colour-coded packaging for clear guidance on which product to use next.

High alkalinity is manageable with the right approach—and the right products. Keep your water balanced and your spa experience stress-free with Spa Fuel.

Insta4 Test Strips

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pH Minus (1.5KG)

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