How to properly balance your spa water

1. Total alkalinity: the cornerstone of balance

Alkalinity is the first measurement to check. It acts as a buffer to stabilize the pH. Incorrect alkalinity causes constant pH fluctuations.

  • Ideal value: between 100 and 150 ppm.
  • Tip: Always adjust the alkalinity BEFORE correcting the pH.
Water test result - Total Alcalinity

2. pH: the core of chemical balance

The pH determines whether your water is acidic or alkaline. An unbalanced pH can damage equipment, irritate the skin, or reduce the effectiveness of chlorine/bromine.

Ideal value: between 7.2 and 7.6.

Water test result - pH

3. Disinfectant – Chlorine or Bromine: for pure water

The disinfectant kills bacteria and algae. Either one can be used, but it is important not to mix them.

Target values:

  • Chlorine: 3 to 5 ppm.
  • Bromine: 3 to 5 ppm.

🔄 Never apply a shock treatment without first testing and adjusting the alkalinity and pH.

Water test result - Free Chlorine Water test result - Total chlorine

4. Calcium hardness: avoid corrosive or scale-forming water

Hardness measures the level of calcium in water. Water that is too soft becomes corrosive, while water that is too hard causes limescale deposits.

  • Target value: 100 to 200 ppm.

💡 Pay particular attention to this in areas where municipal water is naturally soft.

Water test result - Total hardness

Calcium hardness too high

You must remove some water and replace it with fresh water.

5. Stabilizer (Cyanuric acid): protect chlorine from the sun

The stabilizer acts as a “sunscreen” for your chlorine. Without it, chlorine degrades quickly under UV rays.

  • Ideal value: between 30 and 50 ppm.

⚠️ Too much stabilizer can reduce the effectiveness of chlorine: test regularly.

Water test result - Cyanuric Acid

Stabilizer too low

Spa chlorine/bromine already contains a stabilizer, so there is no need to add any. Simply check the level from time to time.

Stabilizer too high

You must remove some water and replace it with fresh water.

🧪 Tip: Test often, adjust precisely

Get a complete test kit or Trévi multi-parameter test strips to monitor these five aspects. Our branch experts can also analyze your water for free in store and offer you a personalized plan.

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