Why Testing your pH & Alkalinity is Important

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Many people believe that if their hot tub water is clear then there is no need to test and balance the pH and alkalinity. Unfortunately this misconception costs spa owners tens of 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. I will explain what imbalanced water chemistry can do to your spa, and how to prevent the costly damage.


Low pH

Low pH causes water to become acidic. This will lead to corrosion in your plumbing and on the spa equipment.

Low pH is very common because your oxidizing shock acts as a natural pH Decreaser, gradually lowering the pH level with each use.

The purpose of oxidizing shock is 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 become cloudy and serve as a buffet for new bacteria.

So while you can’t stop using the oxidizing shock to alleviate your low pH problem, you can keep your pH in check by using Easy pH (the only product available that raises pH but not Alkalinity).

Test your spa water once per 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 Alkalinity

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



Low Alkalinity

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

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


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.
  • 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.
  • Remove a sample of the spa water into a clean plastic cup and test it after it has cooled a few minutes, for best results.
  • Never mix different chemicals together prior to addition 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 prior to 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 bather load.


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 are 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.



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