How Much Baking Soda Do I Add to Raise Hot Tub Alkalinity?

Maintaining the correct level of alkalinity in your hot tub’s water is critical. While you can buy expensive chemicals, you might be surprised to learn you can also use baking soda. But how much baking soda do I add to raise alkalinity in a hot tub?

Here’s what I found out after testing it:

To raise alkalinity, use 1 tablespoon of baking soda per one hundred gallons of water in your hot tub. So the average medium-large hot tub, which holds about 600 gallons would use 6 tablespoons to raise the alkalinity.

After that, allow to circulate, and test and adjust again as necessary. But there’s more to know about baking soda, alkalinity, and how they can work together.

So in this article, we’re exploring how alkalinity and pH work together AND how they differ. We’ll also get more into raising one or the other (or both) with just a few tablespoons of baking soda.

After all, you can raise or lower the alkalinity of your hot tub by using certain liquids and chemicals.

But some of these chemicals can be dangerous if mishandled. They can cause severe burns on your skin. However, some common household items can raise pH levels without the added danger of these chemicals.

Keep on reading to determine how to safely raise the alkalinity of your hot tub’s water.

Can you use baking soda to increase alkalinity in a hot tub?

As a general rule, baking soda raises both a hot tub’s pH and alkalinity levels. But it works extremely well to raise alkalinity.

Remember, the proper level for pH should be between 7.2 and 7.8. Baking soda can be incredibly helpful to homeowners who own a hot tub.

If the pH level is higher, it will be too alkaline, and cause the equipment of the hot tub, such as the heating system,  to be damaged.  The alkalinity of your hot tub’s water can absolutely be raised by using baking soda.

You may be wondering, what is total alkalinity?

pH measures the acidity in your hot tub water. By comparison, alkalinity measures the ability of the water to neutralize the acid. So while they interact with each other, they are also very different.

Want to know more about the differences between alkalinity and pH?

Luckily, I cover that in a recent article.  While closely related, they are actually very different and it could be a huge mistake to just look at one or the other on your test strips and not both.

Just click that link to read it on my site.

The ideal alkalinity level of your hot tub should be between 80 and 120 parts per million.

How much baking soda does it take to raise alkalinity in a hot tub?

Use one tablespoon of baking soda per every one hundred gallons of water in a hot tub to raise the alkalinity. For example, if a hot tub holds six hundred gallons of water, add six tablespoons.

First, you will want to read the manual that came with your hot tub or contact your hot tub manufacturer to determine the amount of water your hot tub holds.

Next, turn off the jets of your hot tub. Make sure you know the pH level of your hot tub by using a testing strip.

Add the amount of baking soda you need, depending on the number of gallons of water in your hot tub. Then turn on the jets of your hot tub. This allows the water to circulate. Keep the jets on for two to four hours.

Test the water’s pH again to ensure that it is correct and within safe levels. Also, test the alkalinity level to ensure it is correct. The correct level of alkalinity is between eighty and one hundred and twenty parts per million.

Will baking soda also raise the pH in my hot tub?

Baking soda raises both the pH level in a hot tub, in addition to alkalinity. However, the impact is significantly greater on alkalinity.

You will want to first test the pH level of your hot tub’s water. To do this, simply take a sample of the water and put a test strip in it. Wait a few minutes and check the color of the test strip with the color guide.

If the pH level is too low, you’ll be following slightly different instructions than above.

Baking soda does raise pH levels, but not as much as alkalinity. Simply sprinkle one ounce of baking soda into your hot tub’s water and put the jets on for twenty minutes.

Then test the water’s pH level to ensure it is at safe levels for soaking. You may need to repeat this again if it is not in between the desired level of 7.2 and 7.8.

If you’re curious about using a hot tub with a high pH level, especially the dangers of soaking in it with too high of a pH, make sure and check out this recent article.

Just click that link to read it on my site.

How do I raise the pH in my hot tub without raising alkalinity?

To raise the pH of a hot tub with minimal impact to alkalinity, run the jets and water features to aerate the water which naturally raises pH, but also consider using magnesium oxide powder or muriatic acid. Both of those chemicals will raise the pH while impacting alkalinity minimally.

But you can’t completely raise the pH in your hot tub without also raising the alkalinity at least a little bit.

So if you need to raise pH without significantly impacting alkalinity, check out the Bulk Supplements brand of Magnesium Oxide powder on Amazon Prime.

It has excellent reviews, a great price, and 1 bag will last hot tub owners quite a while. 2 lbs for about 20 bucks, and it comes with free Prime shipping.

Just click that link to see it on Amazon.

It’s impossible not to raise both, but you can still raise one significantly and only raise the other by a little. Let’s recap what pH is. It hasn’t changed since your high school science class.

The range of pH is from zero to fourteen. The middle of this range, seven, is neutral. Anything before seven is acidic, with zero being very acidic. You never want your hot tub’s pH to be any more than 7.8.

Acidic and corrosive water can damage your hot tub.

Additionally, if your pH is above 7.8, other problems can occur. Itchy and red skin can occur for anyone that soaks in a high pH level water. Your water can also become cloudy and scale may form. Equipment such as pipes can be clogged and damaged.

Scale is a chalky, white buildup on the surface of your hot tub above the headline.

It can also buildup within your hot tub’s pipes, which is what can cause clogging and damage. It can cause your heater and pump to fail. Eventually, if the buildup of scale is not fixed, it can cause the flow of your hot tub’s water to be clogged.

Always test your pH level regularly.

If you want to raise your hot tub’s pH level without significantly raising alkalinity, simply use products that are sold for this very purpose. Many different brands of chemicals will do this.

If you ever need to lower the pH level, you can purchase products that do this as well. Be careful of having a low pH, it can be just as damaging as a high pH.

What is the difference between baking soda and alkalinity increaser?

There isn’t a difference between baking soda and most brands of alkalinity increasers that are on the market. Alkalinity increasers that are sold on the market are made out of sodium bicarbonate, or baking soda.

Baking soda is sodium bicarbonate and has been used to raise total alkalinity a lot while only raising pH a little.

Soda ash, or sodium carbonate, will affect both alkalinity and pH very strongly. Most people use baking soda, whether they realize it or not. 

So there isn’t any real difference except the cost. Why go out and buy an expensive alkalinity increaser when you can use good old Arm and Hammer?

Did I cover all you wanted to know about hot tub alkalinity and how baking soda affects it?

Baking soda is a surprising home item that can be used to affect both the pH and alkalinity of your hot tub’s water.

It is made from sodium bicarbonate and will mildly increase pH while increasing alkalinity a lot. There is no way to not raise both, but you can raise one more than the other depending on what you use.

Total alkalinity refers to how your hot tub’s water resists sudden changes in the pH level.

To raise alkalinity by using baking powder, add one tablespoon of baking powder per every one hundred gallons of water in your hot tub.

Then run your jets for two to four hours and test the water’s pH and alkalinity levels. The correct level of alkalinity is between eighty and one hundred and twenty parts per million.

Remember to always check your pH, which should be between 7.2 and 7.8.

Both high and low pH can cause difficulties and damage, both to your equipment and yourself. Itchy eyes and skin, cloudy water, and a buildup of scale are just some of the possibilities.

Photos which require attribution:

Arm & Hammer Pure Baking Soda, 8 oz (Pack of 2) by Kate Ellis is licensed under CC1.0

Hot Tub) by Jennifer C. is licensed under CC2.0


Jeff Campbell

Jeff Campbell is a husband, father, martial artist, budget-master, Disney-addict, musician, hot tub lover, and recovering foodie having spent over 2 decades as a leader for Whole Foods Market.

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