How To Raise Alkalinity In Hot Tub?

Maintaining the correct level of alkalinity is critical for equipment that is used for water circulation, and a good example of such equipment would be a hot tub. Alkalinity is the ability of the water to keep the elements less acidic by maintaining the right pH level.

Low alkalinity is proven to be harmful to your skin and eyes. At the same time, it damages your precious tub in the long run. Hence, sustaining the correct level of alkalinity is a must for tub owners. For beginners, alkalinity or pH level – all these terms might sound alien or right out of a chemistry experiment!

But in reality, these are some basic terminologies for which you shouldn’t need any academic degree to understand. Throughout this article, I have focused on explaining the process of raising the alkalinity in hot tub units in the easiest way possible.

What Is Alkalinity? and How To Raise Alkalinity In Hot Tub?

Alkalinity measures the water’s ability to neutralize acidity by managing its pH levels.

It acts as a buffer if any change is made in the water’s pH value. So, the alkalinity helps to keep the pH level in water stabilized and also less acidic. There are 3 primary types of alkaline salts such as:

  • Bicarbonate
  • Carbonate
  • Hydroxide

What Is pH?

The pH of the water determines which type of alkalinity is dominant in water at the moment. pH is a shortened form of “power of hydrogen” which is a measure of the concentration of Hydrogen ions in water or any liquid.

Water solutions with a high level of Hydrogen ions have a low pH, and vice versa – little Hydrogen ions tend to have a higher pH.

Roles Of Alkalinity And pH In Water

Alkalinity and pH balance are the two crucial factors for determining the suitability of water.  Total alkalinity and pH measurement are not relative measures. Water with high alkalinity always has a pH value of 7 or more, but water with high pH still does not have high alkalinity. The pH range is ideal between 7.2 and 7.6.

If the number is below 7, the water is considered acidic, and too high is regarded as ‘basic’ meaning it contains base elements according to the pH scale formation.

The measure of alkalinity is expressed as “ppm of Calcium Carbonate,” and the desirable range is between 80-120 ppm.

Adverse Effects Of Low Alkalinity On Equipment

Here are some of the effects of low alkalinity on equipment;

  • Corrosion of the Surface: The surface of the tub can be eroded by acidic water damaging the protecting layer of the tub.
  • Risking Heating Elements: Any kind of metal components like pipes, heaters can be rusty if they are in contact with water with low alkalinity. Apart from property loss, it may also create a risk for the user of getting burnt if the pipe breaks down while using.
  • Scale Formation: Calcium scaling is a common phenomenon for such a case of low alkalinity. It makes it difficult to keep the surface clean.
  • Metal Stain: As the metals begin to scour, it leaves some stubborn metal stain which makes the tub look dirty and difficult to take off.

Adverse Effects Of Low Alkalinity On Human Health

  • Stinging eyes and nasal passage
  • Redness and irritation on eyes
  • Dry itchy skin
  • Hair fall
  • Skin infections like spots and allergies.

Chemical Free Process To Raise Alkalinity

You might be wondering by now, how to raise alkalinity in the hot tub – well, let’s start with the most environmentally friendly. Harsh chemicals are commonly being used to raise the Alkalinity of a hot tub which might irritate our skin. But the good news is it can be done through a natural process, using one ingredient only and that holy grail is baking soda (Sodium bicarbonate)!

All we need is just a water testing strip and some baking soda. The measurement: 1 tablespoon of baking soda is required for 100 gallons of water. After that do as follows:

  • Test the water pH level using a water testing strip.
  • Mix the baking soda with water according to the requirement stated above.
  • Turn on the hot tub jet and allow the ingredient to circulate in the water for two to four hours.
  • checkRetest the pH level. If it’s not within the desired range, keep running the process. Eventually, it will reach the desired level.

Maintaining the desired pH level is very important for the safety of our health. One simple technique you can follow is draining and refilling the water regularly to keep the pH level at a preferred quantity without any extra effort.

However, through a water strip test, we can be certain of it and if required, the alkalinity can be raised through the above-mentioned simple process.

Artificial Process To Raise Alkalinity

We have already mentioned that the alkalinity level should be kept between 80-120 ppm. If it’s below that then alkalinity can be raised using different products available in the market which are specifically manufactured for this one job. But you should apply it with caution if pregnant women will be using the hot tub, raising alkalinity in the hot tub is not worth the adverse effects on fetal development. 

Alkalinity Raising Process

  • Test the alkalinity of the water using a testing strip.
  • Add one cupful of Alka Plus to the tub water. It usually increases the alkalinity level one square on the test strip.
  • Turn on the jet and let it circulate in the water completely. Let it rest overnight as it is better to raise the alkalinity gradually.
  • Check the alkalinity level again the next morning. If it still did not reach the desired level, re-run the process.

Water Clarity Process

  • After adjusting the alkalinity level, if still, the water looks green, adjust the sanitizer level. For that add 30 gm, 1 capful of sun boom to the water.
  • Then add 100 gm, 4 cups of spa shock to the water to regain water transparency.
  • After each process turns on the spa jet and lets the water circulate for at least 20 minutes.

After completing the process, it is crucial to let the air pass through your tub. The confined area may create a toxic reaction that is harmful to a human.

Tips And Best Practices

  • Never use pool chemicals in a hot tub. Chemically, the substances are the same but the concentration is denser.
  • If you want the chemicals to work efficiently, change the tub water frequently.
  • At least twice a month, have your tub alkalinity checked by a professional.
  • In case your test strip is continuously giving a low reading, then the strip might be expired. To be sure you can collect a few other water samples from nearby sources and check again.

The correct degree of alkalinity in your heated pool maintains balanced pH and water chemistry. So, when a hot tub comes down how do you increase alkalinity? The solution to this is here.

By adding an increase in alkalinity to the water you may enhance the alkalinity of the hot tub. The alkalinity can also be adjusted by increasing a standard solution to the water such as baking soda. But there was more to learn about boosting your hot bath’s alkalinity and this piece gets into the subject directly.

There is one thing we need to clarify before we enter this topic: buffering capacity or pH are two very distinct things when linked. Because it is described as ‘alkaline’ water which is basic (contrary to acidic) it is simple to understand how often these phrases are befuddled with professionals in the business! However, in other words, the pH is a relative assessment of the alkalinity of a solution as it pertains to water, whereas the total number of alkaloids measured inside the sampling volume of a solution is total alkalinity.

Further Understanding pH Levels 

What’s pH, then? The abbreviation “pH” refers to the hydro strength that measures the hydrogen ions concentration in a particular solution. That’s the actual pH measure. However, when we discuss the basic or acidic nature of a solution we look at how a solution relates to purified water at pH 7. There are no arbitrary number classifications given to acid and basic solutions. Each entire pH interval is 10 times more acidic or basic a substance than this.

How to Increase the Alkalinity of Your Hot Tub

The increase in the alkalinity of a hot tub is not the same as making it more basic or less acidic: the overall concentration of alkaloids is growing in the fluid. Limescale, carbonate ions, hydroxides, and other small alkaloids are the most prevalent form of alkaloids in hot tub water.

The pH in the water buffer of these alkaline compounds is neutral to acids. In other words, the measurement of the water’s resistance to change in pH is complete alkalinity. Alkalinity raises are items that enhance the overall alkaloid content in liquid in a whirlpool.

Low Alkalinity is Also Bad For Hot Tubs

Even though most of the questions that we have covered so far are users, low total alkalinity is harmful again for different elements of your jacuzzi. The shell surface can be grafted, pitted, and can be delaminated also by the protective layer of the shell. Every item made of metal that has a low total alkalinity contact with water may become corrodible and put your heating components, pipelines, and radiators in danger. It may also be possible to scale calcium, making it harder to keep worktops healthy and clear from accumulation.

Recommended Product

Our favorite product is the SpaBoss Alka Rise. SpaBoss devices are required for the correct amounts of whirlpool chemicals (no chemistry degree required). An increase in alkalinity like the SpaBoss Alka Rise can avoid pH swings that can harm moving elements of the hot tub such as piping or jetting as well as compressors, as well as corrode metal objects.

A regulated acidity is a vital component of establishing a healthy and safe hot tub environment in your hot tub. A hot tub that really is foggy, irritant to the face, eyes, or mouth is almost difficult to enjoy.

If the test leads to an increase in alkalinity, this is certainly an improvement that you do not want to go through. In addition, when you use disinfection focused on bromine, the overall alkalinity of your hot tub may decrease more quickly with a granular chlorine system.

The proper acidity of the heating and water circulation equipment in a hot tub is important to keep it alkaline. Hard liquid or dry chemicals are generally used to increase and reduce pH to maintain neutrality between 7.2 and 7.8. These pollutants can cause serious skin blisters when added to the water or they may leak and harm the space in which they are stored. However, a simple home object can increase pH even without the hazards of toxic chemicals.

Why Is the pH Low?

Importance of Measuring pH in Industry

As the entire alkalinity stabilizes the pH level of the tubing, the other is the same as if one lowers. If the pH is low, the TA will also drop to the low end of the scale.

It can first be perpetrated by drivers. Most hot tubs are frequently visited and humans produce lots of contaminants that might change the biochemistry of liquid. This can go from moisturizer and perspiration, chemicals from your bathrobe to pee.

Mother Nature herself might be another explanation. Stormwater, which tends on the acidity edge of the pH scale, is a typical culprit in reducing water is probably alkalinity. You might discover your water is out of balance after a run-down if you don’t use a hot tub cover.

Chlorine may be to blame as well. The alkalinity can be reduced by using chlorine tablets in the tub as these pills are at a lower pH level.

Why Low Alkalinity is Bad News

The alkaline jacuzzi should exceed 80 ppm. If not, the main difficulties begin to take control of the bath:

Green bath

 It’s quite a clear indicator that you have a problem on your hands when hot tub water becomes green. In a neutrally balanced environment, however, algae cannot develop. Algae blooms are practically unavoidable when the alkalinity (and consequently the pH) decreases.


Although most tubes are constructed of fiberglass, water with low alkaline content may nevertheless lead to problems with corrosion. This is possible on steel surfaces like pumping and filters that can be found in the bath or inside the machinery. They probably need to be replaced when degraded, and it may take a fair coin.

The pH Is Going to Vary

 This will enable pH levels to vary dramatically, given insufficient alkalinity in water. You can have an acidity tub for one minute, and an alkali one for the next. This is also known as pH rebound, as occurs whenever pH buffers are not adequate in the environment.

The Bathers Are Irritated

 Low alkalinity water makes it acidic, irritating people in the bath. I’m not talking about an upset but via their eyes, skin, and nasal route, it will physically annoy them. It can cause even breathing distress for some people.

The Bathroom Is Damaged

 In case of low alkalinity, all potential results depend on material, stain, grain and debonding, and breaking of the tub. A vinyl cover can be degraded and over time become rugged and brittle.

Methods to Raise Alkalinity

You can grasp the importance of restoring it to its appropriate level with so many adverse effects from low alkalinity.

To use the following approach, you may increase your tub total alkalinity:

Method #1: Baking Soda

Baking powder (sodium bicarbonate) is a very frequent technique for increasing alkalinity in a whirlpool. In addition, it’s so commonplace to use soda in a beautiful bottle as goods such as Alkalinity Increaser or Alkalinity Up.

Using baking soda for organic cleaning house products Free Photo

You operate with an incredibly safe chemical using baking soda. It was not only easy but it can be simply put into the bathroom and you can get that in any food shop.

Furthermore, compared to the price for a product like Alkalinity Up, you will spend far less on a particular salt.

How can I add it to the hot tub?

Begin by checking the alkalinity of your water. The testing strips, a liquid test kit, and a computerized testing device can achieve it. Once you know the current alkalinity, estimate how much the hydroxide should be raised to at least 80 ppm.

  • Calculate the bicarbonate powder your bathroom needs. Use 1 spoonful of baking soda for every 100 liters of water as a rule. So use 6 teaspoons when you have a 600-gallon tub. This won’t, however, offer you a certain rise in ppm, so you will have to balance some tests and errors.
  • Adjust yourself in plastic gloves and glasses because your eyes do not want baking soda.
  • In a bucket of water, add baking soda to dilute. Remove till dissolved completely.
  • Transfer the liquid into the bath and wait 15 min for it to circulate completely.
  • Recheck & modify the fluid.

Method #2: Soda Ash Caustic Soda May Also Be Used for a Hot Tub to Enhance the pH

In the use of soda ash, the major distinction is that both the TA and pH levels of the water drastically increase, while hydrogen peroxide is a little more moderate. If your pH doesn’t need to change much at first, this may pose a problem.

How can I add it to the hot tub?

  • As normal, check your hot tub liquid in order to achieve the current level of TA. Testing strips, a fluid kit, or a numerical testing device are available for usage.
  • Soda ash should be measured as baking soda with 1 scoop per 100 gallons of water in teaspoons.
  • Place rubber gloves and eyeglasses on your safety equipment.
  • Mix the soda ash into a jug of water to dilute it. Remove the chemical until it is entirely dissolved, using a wooden stir stick.
  • Fill in the hot tub with the solution.
  • Wait for some hours for the full circulation of the heated pool system.
  • Re-test the water and modify the liquid.

How to Restore Your pH

Water rebalancing doesn’t go as scheduled, sometimes, and after boosting alkalinity (more frequent if you use soda ash), you might end up with a high pH. Don’t fear, using acid – either muriatic acid or sodium bisulfate, you can bring this back down. Another alternative is sulfuric acid, although it is rarely used since it greatly increases the amount of the TDS in water.

Sodium bisulfate is a dry acid, and it might be harder for both to deal with, even if not well managed.

Highly corrosive is muriatic acid. You have to be very careful to avoid mishaps that may lead to you in the ER when working with it. It is also the cheaper alternative, thus the approach is the most popular.

Select your poison! Pick your toxin!

Both cooking soda or caustic soda in a hot tub can increase acidity, but baking powder is typically the best way to do it.

The reason for this is that it influences the water pH level at a minimum, whereas soda ash may drastically push the pH and therefore make the water more balanced over time.


A hot bath in a spa tub feels heavenly after a tiring day. But this pleasant experience might turn into a nightmare if proper care is not taken. It is a must to check the alkalinity level regularly and based on that, steps should be taken to maintain the desired alkalinity level. Make sure you are following any instructions on products you purchase for this purpose, to avoid overshooting the mark and unintentionally leaving your hot tub water unbalanced, or else all your hard work will have gone to waste.

Our readers can follow the above-mentioned processes to maintain their tubs. If in doubt, they can take professional help as well. The bottom line is, alkalinity of the tub water should always be tracked for safety purposes. As you can see there are several consequences of neglecting to check the pH level of your hot tub, including health risks. Now that you know how to balance the alkalinity level of your hot tub, you can enjoy that bubbly bath in peace.  

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