Why Testing your pH & Alkalinity is Important

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Many people take a see no evil hear no evil approach to water care: if their hot tub water is clear then there is no need to test and balance the pH and alkalinity. This attitude can cost spa owners thousands of dollars each year in repairs.

The fact is that water can be crystal clear and odorless, and imbalanced water chemistry can still be wreaking havoc on your hot tub equipment. Let’s take a look at what imbalanced water chemistry can do to your spa, and how to prevent the damage it causes.


Low pH

Low pH causes acidic water, leading to corrosion of the plumbing and spa equipment.

A common cause of low pH is oxidizing shock acting as a natural pH Decreaser, gradually lowering the pH level with each use. OxySpa Chlorine Free Oxidizing Shock has overcome this pH lowering effect with special additives to eliminate the drift.

Oxidizing shock is used to break up dead organic matter (killed by your sanitizer) and prevent cloudy water. Without this shock, the dead organic matter will remain in the water causing it to become cloudy and serve as a buffet for new bacteria.

Test your spa water once a week (if using Bromine or Nature 2) or once every two weeks if using CleanWater Blue. Balance your pH and Alkalinity as necessary per your test strip readings.

Ideal pH range is between 7.2 and 7.6.

High pH and/or High TA

pH above 7.6 and Alkalinity above 120 ppm (90 ppm if using CleanWater Blue) results in scale formation on the hot tub equipment. Scale buildup is the leading cause of premature heater element failure.

pH High, TA NormalAdd Alkalinity & pH Down to lower pH. If TA drops below normal range, add
Alkalinity & pH Up to bring it back up.
pH High, TA LowAdd Alkalinity & pH Down to lower pH, then add Alkalinity & pH Up to bring TA back into range. It won’t raise pH above normal range.
pH & TA HighAdd Alkalinity & pH Down to lower high TA and pH.
pH & TA Stubbornly HighAdd Acid Magic to lower very high TA or pH.

Low Alkalinity

Low alkalinity causes your pH balance to drift from one extreme to the other. This is why adjusting your Alkalinity first (during spa start-up) makes balancing your water so much easier.

The ideal range for alkalinity is between 80-120ppm (30-90 ppm if using CleanWater Blue).

pH High, TA LowAdd Alkalinity & pH Down to lower pH, then add Alkalinity & pH Up to bring
TA back into range. It won’t raise pH above normal range.
pH Drifts WildlyCommonly caused by low TA. Bring TA into line with Alkalinity & pH Up as needed
and make final adjustments to pH, if necessary (usually not necessary). Help lock
pH into range with pH Perfect Balance.

Here are some tips to make water balancing trouble free:


  • IMPORTANT: After adding chemicals, allow your water to equilibrate before retesting, especially if you have been having problems with balance. This means letting the water circulate for a few hours, or retesting the next day for accurate readings. For best results, open all air valves and run the jet pumps.
  • Total Alkalinity should be kept between 80-120 ppm (30-90 ppm if using Cleanwater Blue system).
  • pH range is ideal between 7.2 and 7.6. Too low is acidic and will cause corrosion. Too high can result in scale formation.
  • Never mix different chemicals together before adding to the spa water. Add them one at a time. Pre-dissolving granules in a plastic bucket of water is best.
  • Make sure your water hardness is not too low. Adjust it before making final pH and TA adjustments. A good range for calcium hardness is 150-300 ppm. (Hardness adjustment is not normally needed or recommended if using Cleanwater Blue system).
  • Check Total Alkalinity (TA) first, then adjust for proper pH range. Proper TA will buffer pH, that is, it will help to prevent pH fluctuations.
  • Use fresh, high-quality test strips.
  • Excessively high bromine or chlorine levels can result in false pH and TA readings.
  • Change your spa water at least every 3 to 4 months, depending on the bather load.
Bad source water or well water makes balancing difficult.Reduce contaminants using a hose-end water fill filter, such as the PreFresh.

While most hot tub owners have no trouble getting their water into balance, there is great diversity in water types from region to region. Even within communities, someone could be on municipal water while their neighbor is on a well. Minerals and other elements in water can sometimes lead to difficulty getting pH and total alkalinity (TA) into balance. Luckily, no matter what trouble you’re having, we’re here to help!

Have questions about your water chemistry? Comment below for expert assistance!


  1. I’m on well water and use a hose filter to fill tub. But I can’t get ph and alkaline to drop. Used spa down no help


  2. Hi Ruth,
    If you use two or more tablespoons of Oxy Spa after each use, you might consider dropping it to one tablespoon to see if you maintain the same water clarity. Oxy Spa can help drive the pH and Alkalinity down. If you’re not using that much Oxy Spa, or if you reduce the use and the pH and Alkalinity still stay low, It would be a good idea to add pH increaser to your biweekly water treatment. pH increaser will raise both the pH and Alkalinity.
    I hope this helps!
    Thank you,


  3. I have stubbornly high TA and Ph. I am currently using Clearwater Blue. Would it be better to switch to a different sanitizer as it is difficult to get my TA lower than 90ppm. If so what would you suggest?


  4. Hi Rollie,

    I definitely understand the frustration of high TA and pH, but there’s no need to switch to a different sanitizer. No matter which sanitizer you use, you have to bring your TA down to keep your pH at a reasonable level.

    I would suggest using a stronger acid like Acid Magic to lower your TA. Use it in small doses (3TBS per 500gal), let it circulate and then retest. Repeat if necessary. Once your TA is balanced the pH will follow suit.


    If you need more help, let us know!



  5. Hi I am using bromine in a
    Intex portable hot tub. I am plagued with low TA and Ph bounce. I also seem to have chronic low calcium as well. How should I treat this problem is my first question and my second question: my test strips test total chlorine/bromine and free chlorine. My free chlorine level never moves! Am I supposed be adjusting this level or adding chlorine as well? Thanks!


  6. Hi Summer,

    You’ll find that keeping your TA between 80 and 120 will stop the pH bounce you’re experiencing. The first step when balancing your water is setting that TA to between 80 and 120, then the pH to between 7.2 and 7.6. You’ll also want to ensure your calcium hardness is between 150 and 300, as low hardness can lead to excessive foaming and/or discolored water.

    As for your second question, you’ll want to test for total bromine and disregard the free chlorine. Shocking with a non-chlorine oxidizing shock after each use will break-down organic waste contaminants which cause odor and cloudy water, and make your bromine more effective.



  7. I Totally agree i’ve spent 15 years repairing hot tubs because people use tablets and forget there pH levels


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