Why pH Is Important to Maintaining Your Spa

by Tony Turbo.

One of the more common discussions in our spa showrooms is about the pH of your spa water. Though we have all heard the term, most of us are just a bit confused by what pH means and why it is important. Let’s dive into this (no pun intended because you never want to dive into a spa).

What Is pH?

In common language we usually consider pH to be a measure of how acidic water is, though it really is a measure of both acidity and alkalinity. pH is a scale that ranges between 0 – 14, with 0 being extremely acidic and 14 extremely alkaline (also called basic). A pH of 7 is considered neutral.
As some examples, vinegar (which is acetic acid) has a pH of 2, while baking soda has a pH of 9.
To be more technical, pH is also a measure of the concentration of hydrogen ions (H+) in a liquid. It’s a negative logarithmic scale, meaning a pH of 5 indicates 10x more H+ than a pH of 6.

Why Is pH Important in Your Spa?

The pH of your spa water is important for a number of reasons.

  1. High pH (or high alkalinity)
    1. Will result in dry skin, potentially leading to rashes, lesions, and other issues.  Note: Your skin is slightly acidic with a pH typically between 4.5 and 6.2.
    2. Calcium scaling will occur when your spa water pH exceeds 8.0.  Calcium scaling will result in a spa shell that feels very rough (like sandpaper), spinning jets that no longer work, and salt systems not working.
    3. Chlorine’s ability to kill pathogens (efficacy) is reduced as pH increases.  Hence, correct pH is very important to ensure chlorine is actually killing bacteria, viruses, etc.  Bromine’s killing efficacy is also negatively impacted by high pH but to a much lesser degree.
  1. Low pH (or high acidity)
    1. Acids are corrosive and can damage both your spa metal components as well as be harmful to your skin

What Is the Correct pH for Spa Water?

Though some spa water testers say the correct spa water pH is 7.2 – 7.8, we will recommend 7.2 – 7.6. As you can see, this means we want spa water to be just ever so slightly alkaline or basic.
In many areas of the county, the water out of your tap will have a pH somewhat higher than this, often in the range of 8.0 – 8.4. As soon as you fill your spa, you will want to use some Spa Down, or pH Down, to get your spa water in the pH proper range.

Final Thoughts

Here are three other thoughts concerning your spa water pH.

1. The pH of your spa water will change over time for many reasons, including your addition of chemicals, your own impact in using your spa, and various chemical reactions that occur in your spa water.  Hence, you will use pH Up or pH Down to adjust your pH over time.  pH is one of the important chemical tests you complete 2 or 3 times a week.

2. Our Total Maintenance is a powerful pH buffer. This means it will minimize these changes in your pH. However, no buffer will entirely stop these changes.

It is important that you correct your pH to the 7.2 – 7.6 range BEFORE you add Total Maintenance.

3. The chemical activity that occurs in Salt System Spas will gradually increase the pH of your spa water.  For this reason, we recommend:

    1. Adjusting your pH to 7.2, rather than a range of 7.2 – 7.6
    2. Using Total Maintenance.  In addition to its many other benefits, Total Maintenance will help minimize this gradual increase in pH.


Thanks for reading,
Turbo Tony

Thanks for reading,
Tony Turbo

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