What is pH balance?

Unlike total alkalinity, which measures the ability of water to neutralize acidity, pH balance measures the actual relationship between acidity and alkalinity. When these two qualities are equally balanced, water is considered “pH balanced” or "pH neutral."

  • What does pH stand for? The qualities of acidity and alkalinity each result from the potential of hydrogen ions to remain single (increasing acidity) or to bond with oxygen atoms and form hydroxide molecules1 (increasing alkalinity). This "potential of hydrogen" is abbreviated “pH.”

Why test it?

Knowing the pH balance helps you to maintain the water chemistry of your spa, which is important for your comfort and safety. When pH is too far out of balance, this informs which water balancing products you may need to use. Ultimately, it helps to maintain water clarity and avoid eye, nose and skin irritation, plus it protects internal hot tub components.

What is pH balance?

How is it measured?

By means of the pH scale (a numeric range between 0 and 14) pH balance is measured using a test strip. The halfway point between 0 and 14 (which is 7) is considered “neutral.” The target range for hot tub water is between 7.4 and 7.6. The target range is slightly alkaline to compensate for the effects of heat on H20 molecules.1

  • Why is low pH bad? A pH value below 7.2 means the water is becoming more acidic. Without correction, it will begin to irritate your eyes, nose and skin, reduce the effectiveness of sanitizers, and possibly begin to corrode metallic hot tub components.
  • Why is high pH bad? A pH value above 7.8 means the water has become too alkaline, possibly allowing minerals and metals to form deposits and stains. Plus, it may irritate your eyes, nose and skin, and reduce the effectiveness of sanitizers.

Need help?

Use two clean water bottles to collect these samples: 1) a water-supply sample from your water source, and 2) a mid-depth sample of your hot tub water. Seal each sample tightly, label each one and bring them to your nearest Marquis Dealer for testing.

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What is total alkalinity?

What is total hardness?

Testing sanitizer levels

1Hydroxide molecules form when H2O loses a hydrogen ion and forms a different chemical structure (OH instead of H2O).


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