Using Baking Soda in a Hot Tub: How Much to Use and How to do it?

Baking soda is alkaline and can raise the pH of any low-alkalinity solvent in which it can dissolve. It is also added to food and is, therefore, far from toxic. All this makes it a great candidate for pool water and hot tub chemical balancing. But since it is associated with food, you might hesitate and wonder, can I use baking soda in my hot tub?

You can use baking soda in your hot tub if its pH is too low. Baking soda can raise both the alkalinity and the pH of your hot tub and help it achieve the right chemical balance and stability. Its presence can also keep your tub from being cloudy. However, you shouldn’t add too much baking soda.

Below are the pros and cons of using baking soda in your hot tub. Make sure to also read the step-by-step instructions, including, in the end, regarding how you can add baking soda to your hot tub without overshooting your pH target. The instructions cover two methods, both of which require a pH tester like JNW Direct Spa Test Strips.

Pros of Using Baking Soda in Hot Tubs

If you’re thinking about adding baking soda to your hot tub, chances are you already know at least one advantage of making this addition. However, for clarity’s sake, it is worth looking at all the main advantages of using baking soda as a hot tub additive.

Raises Your Hot Tub’s PH and Alkalinity

This is the flagship advantage of and the key reason behind adding baking soda to swimming or bathing water, whether it is in a swimming pool, a jacuzzi, or a hot tub. In the absence of enough alkaline additives, your pool chemicals can be off-balance, creating an acidic environment. Though this acidic environment can kill microbes effectively, it can also be corrosive to your skin and can turn your pool cloudy.

It Makes Tub Water Clear

As mentioned earlier, your hot tub water can get cloudy in the absence of alkaline chemicals. This is mainly because of chloramine presence as well as the acidic environment allowing for excess ammonia to exist in water. 

If you want to know more about the different reasons behind water getting cloudy, check out my post about what makes a swimming pool cloudy. The same factors affect a hot tub as well, and low pH due to the absence of alkaline chemicals is definitely a contributor.

You might already know this, and trying to get clearer tub water could be the reason you’re looking to add baking soda to it. If that’s the case, you should make sure to look at the disadvantages section because too high a pH and too low of a pH are two faces of the same cloudy coin. Getting a pH balance tester is a great way to ensure that you don’t add too much acidic or alkaline chemicals to your hot tub.

Alternatively, you can turn your hot tub to saltwater to reduce the pool chemical demand in stabilizing the water environment. Stability is important because it saves you time and money and provides you with a healthy bathing environment. But when it comes to stabilizing your water’s chemical contents, using a saltwater generator isn’t your only option.

Stabilizes the Tub Water

In the instance that you add baking soda to increase your water’s pH or alkalinity, you’re using baking soda as a stabilizing agent. Since this is the number one reason people add baking soda to their hot tubs, one can derive that in most cases, baking soda stabilizes the hot tub’s contents. 

Knowing this means you don’t have to stock up on pool chemicals and play the balancing game. While you must balance your tub water’s pH, you don’t have to keep adding acidic chemicals and alkaline ones until the tub is a chemical soup. Simply using smaller doses of baking soda with frequent pH testing can save you a lot of money when it comes to stabilizing pool chemicals, which brings us to the substance’s greatest unspoken advantage.

Cheaper Than Other Alkaline Alternatives

The greatest pro of using baking soda is rarely the one discussed publicly: it is cheaper than other alkaline alternatives. You can surely use a contact-safe soluble alkaline substance to turn up your hot tub’s pH until it is at the desired level and well-balanced. ‘

But the reason people use baking soda for hot tubs and pools is simply that it is cheaper. How cheap? You can save at least $100 per balancing cycle by opting for baking soda instead of other alkaline alternatives for your swimming pool. Depending on your hot tub’s size, this could translate to $15 to $35 in savings per balancing attempt. This doesn’t consider the ease of balancing and acquisition, which can further save you money.

Easy to Acquire and Use

Finally, the fact that you’re reading this article speaks to baking soda’s superiority as an alkaline additive. Since the product has been used commonly by swimming pool owners and those with hot tubs, there are plenty of educational resources like the video below that show how you can raise your tub’s alkalinity by adding baking soda to it.

Furthermore, the product’s collective popularity means it is easily available at stores around the corner and even on amazon like Milliard Baking Soda. Because of its abundant retail availability, it is often cheaper to order and ship, even from online stores. Other alkaline chemicals might go out of stock, not be available, or ship from other countries, making things quite inconvenient. From a shorter waiting period to a lower price, baking soda is a bargain when it comes to maintaining your pool’s pH and clarity.

The Cons of Using Baking Soda in Your Hot Tub

While baking soda can be a cheap alkaline additive, this can become a drawback-hydra. Just like it is easier to overeat at a cheap junk food spot than it is to do so at a fine dining establishment where 70% of your plate is bare and 90% of your wallet empty, it is easier to overuse alkaline chemicals that come by the bucket compared to ones that really hurt your wallet. The reason I call this a drawback-hydra is that it has three heads, and these off-shoot disadvantages are covered below.

It Reduces the Effectiveness of Chlorine

If you add too much baking soda to your tub water, the chlorine you’ve added becomes impotent and unable to kill bacteria. These bacteria can then create an ammonia-rich environment that can turn the pool cloudy, but that’s a different drawback. The reduction of chlorine’s effectiveness is mainly a problem because it is truly the most important chemical in any pool of water. The higher your water’s pH, the likelier it is to have microbes. 

And if your hot tub’s source of chlorination is a saltwater chlorinator, then you should definitely reduce the amount of baking soda you add as the chlorine content of your water is already too low to be nerfed by baking soda.

Causes Cloudy Water

As mentioned above, higher pH can create an ammonia-rich environment because of bacteria. It can also allow algae to grow, which can also cause cloudiness. If you’re adding baking soda just because your water is cloudy, make sure you check its pH first because it might not be the absence of alkalies but their abundance that could be causing the cloudiness.

Can Lead To Deposits in the Tub’s Plumbing and Interior

Finally, the problem with too much baking soda in your hot tub is that it turns water hard. The harder (or more alkaline) your hot tub, the more difficult it is for calcium to dissolve. Calcium deposits can form in the tub drain, filter pump, and even worse, the heat pump. 

Furthermore, the same hardness can cause skin irritation, allergic reaction and make it impossible for bathing soap to dissolve. Hopefully, this can make you appreciate the “hydra” in the drawback-hydra that is too much baking soda.

How to Add Baking Soda to Your Hot Tub

You’ve done well, choosing baking soda as your alkaline additive for your hot tub. And it’s even better that you’re looking up how to do it because too much baking soda (As covered above) can cause problems down the line. The best way to add baking soda is to simply do it just enough that it gets your tub’s alkalinity exactly as high as you want it. This raises the question of how much baking soda to raise alkalinity in my hot tub is enough?

To raise alkalinity in a hot tub using baking soda, you must add six tablespoons. The ideal ratio is one tablespoon per hundred gallons, given that the water isn’t alkaline enough, to begin with. Otherwise, you have to test the pH and add tiny increments and retest until the pH is between 7.2 and 7.8

Adding baking soda to your hot tub isn’t rocket science, but there are steps that keep you from adding too much. And they start with finding out your pool’s pH. Below are two methods to add baking soda to a hot tub.

Ratio and Tablespoons Method

This method is for individuals who know how much water their hot tub can hold. Usually, the tub’s manufacturer discloses this on the packaging or the sales page. If this information is missing, you will waste too much time trying to pull this off. Skip to the next method if that’s the case. Otherwise, do the following.

  • Write down the amount of water in your hot tub by the gallon.
  • Divide the number by 100.
  • The answer is the number of tablespoons of baking soda you need to add to your hot tub.


This method relies on the fact that an average of one tablespoon per hundred gallons creates the right alkaline balance. However, water’s natural alkalinity might vary depending on the region and the previous stabilization attempts. That’s why testing the pH after putting half the number of required spoons is a good idea. An even better, albeit longer, method relies on more testing and is detailed below.

pH Per Spoon Method

In order to pull off the right balance, you need to know the level of pH or alkalinity raised by a spoon of baking soda. For average pool water, a tablespoon raises the pH for a hundred gallons and brings it to an alkaline sweet spot. But if you don’t know how many gallons of water your tub has or whether your water is already alkaline to an extent, you can use the following method.

  • Test the pH of the water. Starting off by knowing exactly how much pH you should raise is a great way to ensure that you don’t add too much baking soda. As mentioned earlier, the safe pH range for a hot tub is 7.2 to 7.8.
  • Add one spoon of baking soda, and measure the increase in pH after circulation. Upon adding a tablespoon of baking soda, you will not see an immediate rise in pH. This can also be a contributor to over-spiking tubs with soda. Wait 15 minutes and let the water circulate before taking a pH reading. Subtract the new reading from the previous one, and you’ll have the pH per spoon.
  • Add the required number of spoons. Now that you know how much pH rise occurs per spoon of baking soda, you can calculate how many spoons you need and add that many before circulating and retesting.


In case you’re not clear on how to finalize the number of spoons, take the following steps to get the right mathematical number. 

  • Subtract your latest pH reading from 7.2; that’s the required pH increase.
  • Divide the pH increase required by pH per spoon.
  • Whatever number you get is the number of tablespoons needed. Since we’re going by the lower pH limit, you can safely round up.

Final Thoughts

Baking Soda is a cheap and effective alkaline additive that can be used to balance the pH of your hot tub. However, going overboard can have consequences that are just as bad as not using baking soda at all. It is therefore essential to add the soda in small increments and regularly test to make sure just the right amount is added.

Jed Arnold

Jed spent every year from the ages of 15 - 22 as a Lifeguard (Red Cross) and ages of 17 - 22 as a Certified Pool Operator (CPO). Between working for over a dozen facilities and owning a pool, he carries over a decade of pool experience.

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