How To Raise Alkalinity In Hot Tub

How To Raise Alkalinity In Hot Tub [Quick Steps]

Many people dream of unwinding in their hot tub after a difficult day. However, you could discover that after a relaxing soak, your skin feels dry. The cause could be the low alkalinity of your hot tub.

How then can you bring the alkalinity levels back to the desired levels? Adding baking soda or soda ash to a hot tub is the most significant approach to increase its alkalinity. In this article, you will learn how you can raise alkalinity in hot tubs.

How To Raise Alkalinity In Hot Tub

What Is Total Alkalinity?

Total alkalinity essentially hampers the water’s capacity to absorb pH changes. The amount of dissolved alkali in the water is measured as total alkalinity. The pH level of the water is regulated by these components. When water is being treated with pool chemicals, this rule is crucial.

Some chemicals might change the pH after being added to your tub. For instance, the pH of the water will fluctuate dramatically in the absence of a healthy total alkalinity level. The substance that affects pH will react with total alkalinity and be neutralized. and subsequently, keep the pH level constant.

The pH level is not, however, determined by total alkalinity. Instead, it assists in maintaining the pH range that is desirable.

How To Increase Alkalinity In Hot Tub?

Baking soda and soda ash are the two substances that are most frequently employed to increase total alkalinity. Soda ash will raise pH, whereas baking soda will very slightly affect pH, making this difference between the two compounds.

Baking Soda

A perfect chemical is baking soda (sodium bicarbonate), as it is completely safe to use. Additionally, you can find it in the baking section of most supermarkets. Thus, the best choice is baking soda if the hot tub’s pH measurement is normal.

One tablespoon (tbsp) of baking soda should be added for every 100 gallons (379 L) of water, according to the common rule of thumb. As a result, to increase the overall alkalinity of a hot tub that is 400 gallons (1,514 L), add 4 tbsp of baking soda. The baking soda dosage for 500 gallons (1,893 L) of hot tub water is approximated in this table.

You can read: How Much Baking Soda To Raise Alkalinity In Hot Tub?

Total Alkalinity IncreaseBaking Soda Amount
10 ppm1.2 oz
20 ppm2.4 oz
30 ppm3.6 oz
40 ppm4.8 oz
50 ppm6 oz

Soda Ash

soda ash

Although they resemble one another, you must handle soda ash (sodium carbonate) carefully. When using this product, safety gear and proper ventilation are required. However, if you need to dramatically increase your pH as well as alkalinity, this is the best option.

The general rule is to use one tablespoon (tbsp) for every 100 gallons (379 L) of water, just like with baking soda.

Adding 1.2 ounces of sodium carbonate (soda ash) to 500 gallons (1,893 L) can significantly increase the pH and raise the alkalinity by 10 ppm. contrary to baking soda. However, the chemistry of the water and the water temperature will determine exactly how much the pH and alkalinity increase.

How To Apply

When applying it to your hot tub, there isn’t much of a difference between using baking soda or soda ash. The main distinction is that when handling soda ash, you should always wear safety gear.

Keeping your pool baking soda separate from your regular baking soda will assist in preventing cross-contamination even though you can buy baking soda at most grocery stores.

  1. Test the water: To start, use pool chemistry test strips to check the hot tub’s chemical balance. Then figure out how much more total alkalinity you’ll need to add to get it to at least 80 ppm.
  1. Measure the Baking Soda/Soda Ash: Wear gloves and safety glasses. Although it is safe, baking soda might irritate your eyes. Therefore, developing this habit while using either drug is ideal. To get it to 10 ppm, you’ll need roughly 1.2 ounces per 500 gallons (1,893 L) of hot tub water. To be certain of how much you require, use the table above.
  1. Pour the solution: Dissolve the calculated amount of soda ash or baking soda in water completely. Add to your hot tub and give the water at least six hours to circulate. Use roughly half of what you anticipate being required to begin.
Pour the solution in hot tub
  1. Retest the water: To receive a new reading, use a different test strip. Until you get the desired 80-120 ppm, repeat the steps. If the reading is low calculate how much you need and add more to the hot tub. Always keep in mind that you can always add more if it’s too little, but you can’t take it away if it’s too much.

Effects Of Low Alkalinity

Low alkalinity is undoubtedly bad for your hot tub and the people using it, even if it might not be obvious at first. Every time someone enters a hot tub, they introduce impurities that could alter the water’s chemistry.

It could be sweat, the usual bodily oils, or at its worst, urine. Rainwater can, however, decrease the alkalinity of your hot tub if it is outside and exposed during rainfall.

Here is a summary of potential outcomes should levels fall below the recommended range:

  • First off, the effectiveness of sanitizer chemicals is reduced, and pH levels will vary substantially.
  • A hot tub with low alkalinity can irritate the skin and eyes.
  • It may result in surface damage to your hot tub, such as discoloration, microscopic cracks, and pitting.
  • Low alkalinity levels make water more acidic, which can lead to corrosion of crucial parts of hot tub piping and heating systems.
  • It is a costlier operation since you’re always operating your jets to try to balance your pH without addressing the root cause of the issue

How Long Does It Take To Increase The Alkalinity Of A Hot Tub?

How long it takes to raise alkalinity is unfortunately an open question. Everything depends on the size of the hot tub and how much the ppm needs to be raised.

The time it takes to boost your hot tub’s total alkalinity will depend on how far it is below the ideal range (80-120 ppm). As a result, it will probably require numerous applications of baking soda or soda ash, each requiring at least six hours of circulation.

The other key decision aspect is the hot tub’s size. It makes sense that the smaller it is, the quicker the alkalinity will be raised. A larger hot tub may require considerably longer because there is more water to circulate.


Should you first increase pH or alkalinity levels?

The golden rule of hot tub water maintenance is to always increase the alkalinity first. Once the hot tub’s alkalinity is satisfactory, perform another test to determine the pH of the water.

Can vinegar be used to lower the alkalinity in a hot tub?

Many individuals make the error of believing that adding vinegar to a hot tub can lower alkalinity. But it doesn’t; in fact, it will lower the pH.

Is using a hot tub with low alkalinity safe?

Low alkalinity levels in hot tubs can irritate the skin and eyes. Additionally, it lowers the effectiveness of sanitizers, requiring much more of them to keep bacteria at bay.

If you already have higher alkalinity in your hot tub, you can read the bad effects of your hot and what cause can happen.


Hi, I'm Shimul, the founder of Pooltub Life. I'm excited about sharing the latest outdoor living trends with you. My goal is to provide you with up-to-date information that will help make your POOL & HOT TUB stylish and enjoyable. Read About Me More । Follow on Facebook

Leave a Reply

Your email address will not be published. Required fields are marked *