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Managing pH in Your Hot Tub

Balancing Act: Managing pH in Your Hot Tub

pH is the abbreviation for the power of hydrogen and is an essential factor in your hot tub’s water chemistry. The H is capitalized pH because it is the element symbol for hydrogen. In this featured article, I will impart all of my pH knowledge so you better understand what pH is, how it affects your hot tub, and how to fix it.

As You Read Through, I Will Answer These Essential Questions About Hot Tub pH

There often needs to be some clarification about pH and alkalinity regarding water chemistry. The misconception is that these are the same thing. Alkalinity measures calcium, magnesium, and other acid-moderating compounds acting as a buffer for pH change. It is essential to understand alkalinity because it helps stabilize the pH balance, preventing sudden pH changes in your water and thus keeping the pH within a normal range.

What Is ph And Why Is It Important To Your Hot Tub

pH measures how acidic or alkaline your water is and is essential to your hot tub water chemistry. When your pH is within the correct range, your water is considered neutral, which means it’s not too acidic or too alkaline, preventing damage to your hot tub equipment.

PH Good for your waters Health

The recommended range of pH should be between 7.2 and 7.6. When testing and adjusting your water. pH is always the second factor you test after Alkalinity. If you go back to my post about alkalinity, I discuss how proper alkalinity prevents sudden changes in the pH, often called bounce.

Your pH can easily be tested with a drop kit or test strips. I prefer a drop kit for color accuracy. You can find my recommendations in my swim n soak store.

Low pH

Low pH can cause eye and skin irritation. Acidic water can sting your eyes and nasal passages and strip you of natural oils, making your hair brittle and leaving your skin dry and itchy. Low pH can also lead to equipment corrosion and shorten its life. Similarly, when the pH drifts too high, minerals will precipitate out of the water, which can cause scaling and murky water from the mineral deposits left in the water.


High pH

High pH causes your water to become alkaline, and minerals will precipitate out of the water, which can cause scaling on your shell and equipment. In addition, your water will look murky from the mineral deposits left in the water.

How ph Effects sanitizer

Besides protecting your equipment from premature failure. Another reason to keep pH in range is to maximize the effectiveness of chlorine and other sanitizers.

For chlorine efficiency and other sanitizers, you should keep your pH between these values. For example, a pH level of 7.5 ppm equals 45% useable chlorine, while a pH of  8.0 ppm equals 25% usable chlorine. Keeping your pH within the range maximizes your chlorine’s effectiveness and how well it does its job—saving you time and spending less on chlorine.

What Causes PH To Rise

What Causes PH To Rise? most likely, it’s your water source. It may already be high in pH. As you add sanitizer, it can also have an impact on the pH. Dichlor, like bromine, is the best and has a relatively neutral pH, so its pH impact is minimal.

Other chlorine’s, such as sodium hypochlorite (liquid chlorine) and chlorine generated by a salt system, are perfectly fine but have a high pH and will eventually raise the pH. So, you will have to monitor your water for any changes.

A type of chlorine I don’t recommend is non-stabilized chlorine, like calcium hypochlorite. It can cause problems with your alkalinity, pH, and hardness all at the same time.

Often forgotten about is Agitating the water with your jets and waterfalls. Running causes carbon dioxide to leave the water. This results in an increase in the hydroxide ions, which causes the pH to increase.

What Causes PH To Lower

What Causes PH To Fall? As with high pH, your water source may be low in pH. Also, rainwater can be acidic. Heavy downpours can reduce the pH of your hot tub if the cover is left open.

Organics like Leaves, bugs, grass cuttings, etc., will all contribute to lowering the pH. Our sweat leaves bodily oils, saliva, and other bodily fluids all combine to reduce the hot tub’s pH.

In addition, chlorine tablets with Trichlor are also not recommended for hot tubs as they have a very low pH of around 2.8 combined with cyanic acid, which makes them a bad idea.

How To Increase PH

water testing

You can use any number of chemicals to raise the pH of your hot tub. They usually have names like “increaser,” “up,” or “raise.”  Depending on the manufacturer, pH down is available in both power and liquid forms and should have dosing directions on the label for your size tub.

Whatever you use, they are all based on Sodium Carbonate, known as Soda Ash. Not to be confused with Sodium Bicarbonate, aka baking soda. I recommend when adjusting pH it is easier to use a pH-only product. As you become better at water chemistry, Baking Soda has the advantage of raising pH and alkalinity simultaneously.

Let me explain.If your alkalinity and pH are closer to the low end of the scale, you can use baking soda to raise both simultaneously.

For example, your alkalinity is at 70 ppm, and pH is at 7.0 ppm. Adding a little backing soda should raise both back into range and get you back to soaking.

When they are further apart, one is very high, and the other is very low. Do not use backing soda and adjust it separately from pH.

When making adjustments to pH, always do them gradually. It’s better to do small doses rather than attempting a major one. You don’t want to overshoot the mark with too many chemicals, forcing you to start over.

After you make your initial adjustment, you only need about twenty to thirty minutes before you retest to verify your success.

How To Lower PH

Lowering pH is much the same as raising it. In this case, you would use Sodium bisulfate, which often comes in a powder form. Be careful on windy days. 

When adding Sodium bisulfate, get as close to the water as possible to avoid the above-mentioned blow-back. You want to avoid blow-back to your skin and clothes, as this is a type of acid. 

Wait at least six hours before retesting to ensure your level is correct. Note pH takes more time to adjust. You may have to reapply over several days for your pH to fall into range.

ph far

PH Questions and Answers

PH Is Always High

The most common reason for a high pH is using liquid chlorine or a saltwater system as your primary sanitizer. Both will raise pH levels.

PH Is Always Low

The most common cause of low pH levels is using chlorine tablets or stabilized chlorine. They have a pH level of around 3. Acidic rainfall, heavy leaf debris, and dirt/mulch can lower your pH levels.

PH Is Low, Alkalinity Is High

High Alkalinity over 120 ppm can cause resistance to pH change. Also, adding a pH Increaser can also raise Alkalinity, compounding the problem.

PH Is High, Alkalinity Is Low

Low Alkalinity under 80 ppm can cause pH to be unstable and erratic. To raise Alkalinity, add Alkalinity Increaser, which will slightly increase your hot tub pH level.

PH Will Not Increase Or Decrease

Adding a pH Increaser or Decreaser only lasts a day and may not completely take effect.  Keep replying until the proper level is achieved.

Is It Safe To Soak In High/Low PH /Alkalinity?

Your pH and alkalinity can affect disinfection by chlorine. Chlorine is very slow to react at high pH levels and can be over 50% inactive at a pH above 8.2. However, even with high pH, the water could still be sanitary and be able to be used. Check the free chlorine levels to verify.

In Conclusion

In conclusion, maintaining the proper pH balance in your hot tub is just part of the soaking experience. It’s crucial to keep your pH within the recommended range of 7.2 ppm to 7.6 ppm, and understanding the role of alkalinity in pH stability is vital. Low or high pH can lead to various issues, from irritation to equipment damage.

We’ve also explored the factors that influence pH levels and discussed methods for adjustment.

By taking these insights to heart, you can ensure your hot tub remains a haven of relaxation while saving time and money on chemical treatments.

Next Step's

Now that you’ve gained a deeper understanding of pH’s crucial role in your hot tub’s water chemistry, it’s time to take action and ensure your hot tub experience remains safe, enjoyable, and efficient. Here’s your call to action:

  1. Regularly Test Your pH: Make it a habit to test your hot tub’s pH levels using a reliable kit or test strips. Keep a close eye on this essential factor in water chemistry.
  2. Adjust pH as Needed: If you find that your pH is outside the recommended range (7.2 to 7.6), take action to bring it back into balance. Use the appropriate chemicals, such as pH increasers or sodium carbonate, based on your specific pH and alkalinity levels.
  3. Monitor Alkalinity: Understand the role of alkalinity as a buffer for pH stability. Maintaining proper alkalinity levels is crucial for preventing sudden pH fluctuations.
  4. Stay Informed: Continue to educate yourself about hot tub maintenance and water chemistry. Knowledge is key to ensuring a safe and enjoyable hot tub experience.
  5. Enjoy Your Hot Tub: By following these guidelines, you can relax in your hot tub with confidence, knowing that your water is perfectly balanced and your equipment is protected.

Your hot tub should be a source of relaxation and enjoyment, and with the right pH balance, you’ll have countless soothing soaks to look forward to.

Need ph incresser or decresser. I have great products including Total Alkalinity Increaser available in my swim n soak store.


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