How Much Baking Soda To Raise Alkalinity In Hot Tub?

How much baking soda to raise alkalinity in hot tub

Being able to soak in a hot tub is one of the first things everybody will want after a hectic day. It helps you release the mental and physical stress to the tub of hot water. To enjoy such a blissful soak, your hot tub water must be well-balanced. By balance, I not only meant keeping the water visually clean, and germ-free but also keeping the water’s chemical elements and their determiner’s level in control. Such as, your hot tub water alkalinity level can fall leading pH related issues to your hot tub.

There are many DIY and purpose-built alkalinity raisers, such as baking soda. Now if you face a similar issue with your tub alkalinity level and considering using baking sodas, then you might also be wondering about their amount of use. Well, for your relief, the standard baking soda amount per 100 gallons is 1 tablespoon, equivalent to 5 grams. Continue your reading to find out more about the baking soda amount to raise the alkalinity level in your hot tub. Apply baking soda as per the information provided below and thank me later!

What Does ‘Alkalinity Raise’ Mean?

What does ‘alkalinity raise’ mean
What does ‘alkalinity raise’ mean

Before jumping into the amount of baking soda to raise alkalinity in a hot tub, first, you have to understand some basic terms regarding alkalinity and its raising. In the process, we will mention a lot about tub water pH too. That’s why, let’s understand both and their inter-relation. 

Total Alkalinity: The alkalinity level tells you the buffering capacity of the hot tub water. Buffering is the ability of the water to resist pH changes. An alkalinity test results you the buffering capacity in the basic pH range of the water. pH in the water doesn’t change by itself. There could be more than one chemical or water element that influences water’s pH level to rise or reduce.

However, the water’s alkalinity feature prevents these chemical abnormalities from happening and keeps the water pH neutral. When water starts to lose this feature for some reason, it is called a low alkalinity and it needs to be risen to normal.

pH: Talking about pH, it is a way of measuring the concentration of hydrogen ions within a given solution. Naturally, the neutral pH level is 7.4. Anything lower than that pH means the hot tub water is acidic, whereas a higher pH reading indicates the basic characteristic of it. Water being too acidic or too basic has con sides, especially when it is your hot tub’s water. The water alkalinity feature allows its pH level to be as close to the neutral level, meaning the water is ideal for use.

How Do You Know If Your Hot Tub Has Low Alkalinity?

How do you know if your hot tub has low alkalinity
How do you know if your hot tub has low alkalinity

Low alkalinity can be caused by contaminants from bathers, overuse of alkalinity-lowering products, overuse of chlorine tablets, and excessive rainwater.  Water’s optimal alkalinity level is between 80-120 ppm (parts per million). If your hot tub’s water alkalinity level falls, you won’t be able to notice the impacts as they will be too subtle. If not tested for alkalinity, as time goes by, you will see symptoms like:

  • Corrosion of Metal Parts: Low alkalinity means possible lower pH of the tubs water. And lower pH means there is acidic element in the water. This can gradually create corrosion in the metal parts of the tub such as the water jet, draining hole, pump, pipes, etc. This can also put stains on the tub surfaces.  
  • Foamy & Cloudy Water: Due to low alkalinity, you will see your tub water getting foamy and cloudy. This happens because of mineral chemicals such as calcium carbonate buildup. Also, chlorine used for cleaning the water will be less effective and you will have to use more. Altogether these will make your hot tubs water foamy and cloudy.
  • Itchy and Dry Skin: Soaking in low alkalinity and pH water will likely impact your skin. Skin’s moisture level can be impacted in this way. This can lead your skin to feel itchy and dry.
  • Burning Sensation to Eyes & Nose: You will feel physical symptoms such as a burning sensation in your eyes and nose. Chemical imbalance caused by low alkalinity can trigger physical anomalies such as Rhinitis.

If you haven’t checked for such alkalinity levels in recent times but have felt such anomalies in your tub’s water, then there is a high chance that your hot tub water has a low alkalinity issue.

How Much Baking Soda To Raise Alkalinity In Hot Tub?

The general infinite rule is to use one tablespoon (5 grams) of baking soda for every 100 gallons (379 L) of water. But this can vary based on your hot tub size and the amount of water in it. If you consider the hot tub can has a 500-gallon capacity then you will need, (500/100) multiplied by 5 grams, equal to 25 grams of baking soda. Applying this amount of soda can increase the alkalinity level to 10ppm in that hot tub water.

So if your hot tub’s water has alkalinity lower than 80, take 50 ppm as an example and you are aiming for a range of 80-120 ppm, and adding the baking soda might bring it up to around 70 ppm. It’s not an exact science, but starting with that assumption seems like a reasonable plan. Let’s make a chart for your easy understanding:

60504030252015105Soda (In Grams)
PPM1000800600500400300200100Tubs Capacity (Gallons)

Note that, these figures don’t represent the exact amount of baking soda for rising alkalinity levels to an exact extent. The results can vary depending on your water’s alkalinity intensity. They are based on calculation as per standard use amount. But one thing is for sure these are pretty safe figures to apply, that’s for sure.

How To Use Baking Soda To Raise Alkalinity In Hot Tub?

How to use baking soda to raise alkalinity in hot tub
How to use baking soda to raise alkalinity in hot tub

Now you have a better idea of how much baking soda you should use to raise the alkalinity level of your hot tub. But do you know how to use them? If not then we have covered that too. Because applying baking soda improperly can backfire by raising the pH level higher than required. You will need some materials to do the task properly.

You Will Need:

  • Alkalinity Test Kit
  • Baking Soda (sodium bicarbonate)
  • Safety Gears
  • Bucket (For External Mixing)

The Process

  • Start with testing your hot tubs water’s alkalinity level by using the alkanilinity test kit.
  • Find out the current amount of water in your hot tub. It should be written on the tubs surface( marked with lines) or follow users manual.
  • Determine how much alkalinity level you want to rise. Calculate the amount of baking soda needed too. (You can follow the chart mentioned above).
  • To apply the baking soda into the hot tub properly, first pour required amount of baking soda in a half-full bucket first.  
  • Pour the preliminary mix into the hot tub slowly. Switch on the pumps and leave it for 6 hours, covered off.
  • Retest the alkalinity and pH level to sense the result and adjust if necessary.

Some Other Benefits Of Using Baking Soda To The Hot Tub

Some other benefits of using baking soda to the hot tub
Some other benefits of using baking soda to the hot tub

Apart from or in the process of raising your hot tub’s water alkalinity level, using baking soda in the hot tub can have some additional benefits. Such as:

  • Makes Hot Tubs Water Clean: Lower alkalinity means chloramine presence as well as the acidic environment allowing for excess ammonia to exist in water. It leads the water to be cloudy and heavy. After restoring your hot tub’s alkalinity level using baking soda, you will find your water cleaner than before.
  • Easy To Source & Use: One of the major reason for using baking soda to raise the hot tub’s alkalinity level is they are easy to source and apply. Baking sodas are common in household kitchens. A pound of these baking soda costs as little as $2-$3. They can be bought from any general store easily and their application process is very simple. On the other hand, a purpose-built alkalinity raiser can cost more than $10, a pound to purchase.
  • Stabilizes Hot Tubs Water: Retaining your hot tub water’s ability to control its pH to the required label, helps your tubs water to be chemically stable. If not the soda, you had to use different types of chemical products to solve different water issues. This surely gave you the headache of playing water-stabilizing games frequently. Using baking soda after testing your water at regular intervals can help the water to be stable and prevent water from causing the body and hot tub hardware issues.

Final Thoughts

Filling your hot tub with water is not everything to have comfort hot soaking regularly. Apart from cleaning the hot tub, plumbing setups, and the water itself visually, you need to ensure that the water’s chemical element structure is also on the right track. Keeping the alkalinity level to the required level is surely one of them. Alkalinity ensures water standard resistance against reducing or increasing its pH level abnormally and keeps the water fit for use. Using baking soda is one of the most efficient methods to raise a downed alkalinity level. It usually starts from 5 grams from each 100 gallons of water. Use precision to measure, calculate, and application of baking soda to your hot tub to properly raise its alkalinity level.

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I am Donald M. Beyer and I am backyard enthusiasts. I am a homeowner who has been doing DIY projects in and out of my house for many years. From simple backyard lunches to making an old-school pizza oven in my own backyard, I have a lot of experience in turning my backyard into my and my family’s personal playground.

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