How to Lower Alkalinity in Hot Tub?

In a hot tub, the correct balance of alkalinity is essential to maintaining the chemical stability of the water and a suitable environment for use. Proper alkalinity can help the water in the hot tub maintain a stable pH value, prevent over-acidification or alkalinization, and provide a comfortable and safe environment for use.

Below, let's learn about what alkalinity is and what methods are used to reduce it?

What Is Alkalinity?

Alkalinity refers to the amount of alkalinity in water and is a measure of the water's ability to resist changes in acidity. It is usually expressed by the concentration of bicarbonate ions (HCO3^-) and carbonate ions (CO3^2-). The higher the alkalinity of the water, the stronger its ability to resist the effects of acidic substances.

Total Alkalinity is a term related to alkalinity. It represents the total concentration of all alkalinity in the water, including bicarbonate ions, carbonate ions, and other alkalinity. Total alkalinity is usually expressed in ppm (parts per million) or mg/L (milligrams per liter).

Is Alkalinity the Same as pH?

Although both pH and alkalinity involve the acid-base properties of water, they are different concepts. pH focuses on the concentration of hydrogen ions in water, while alkalinity focuses on the content of alkaline substances in water and the neutralization ability of water to acidic substances.

★The Concept of pH:

The pH value is an indicator of the concentration of hydrogen ions in aqueous solutions and is usually used to measure the acidity and alkalinity of water. The pH scale ranges from 0 to 14, with 7 indicating neutrality, below 7 indicating acidity, and above 7 indicating alkalinity. Therefore, the lower the pH value, the more acidic the solution; the higher the pH value, the more alkaline the solution.

The United States Environmental Protection Agency (USEPA) regards pH as a secondary pollutant and proposes an ideal pH range of 6.5 to 8.5, which is to maintain the ecological balance and health of water bodies. Alkalinity is closely related to pH, but they are not always converted to each other.

Should I Adjust the Alkalinity or pH First?

Typically, you should adjust the total alkalinity of the hot tub water first, and then adjust the pH. This is because the total alkalinity can act as a buffer, helping to stabilize the pH of the water and prevent it from fluctuating excessively.

When the total alkalinity is within the proper range, the pH of the water is more easily controlled within the ideal range, and the impact of pH fluctuations on water quality and equipment can be reduced. Therefore, adjusting the total alkalinity is one of the important steps to ensure the chemical balance and stability of the water.

Why Control the Alkalinity Balance?

When the hot tub water is high in alkalinity, it will cause the pH to increase, the water to become cloudy, irritate the eyes, throat and ears, and scale on the walls and accessories. Too low alkalinity may cause the water to become more corrosive, thereby damaging equipment components such as pipes and filters.

What Are the Ways to Reduce the Alkalinity of the Hot Tub?

To Reduce the Alkalinity of the Hot Tub, You Can Take the Following 2 Ways:

Way 1: Add acidic substances

Way 2: Use acidic water treatment products

● Add acidic substances: Adding acidic substances, such as sulfuric acid or hydrochloric acid, to the hot tub can reduce the alkalinity of the water. However, this requires great care, ensuring that it is added in the correct proportions and wearing appropriate protective equipment when operating.

●Use an acidic water treatment product: There are products available specifically for adjusting the chemical balance of hot tub water, some of which are acidic and can help reduce the alkalinity of the water. Follow the product instructions.

How to Quickly Reduce the Alkalinity of a Hot Tub?

To Quickly Reduce the Alkalinity of Hot Tub Water, Hydrochloric Acid (Safer than Sulfuric Acid) is Generally Added:

Adding hydrochloric acid to hot tub water can quickly reduce alkalinity. Add 0.05 gallons of hydrochloric acid for every 500 gallons of water. Test the pH as you add the hydrochloric acid to get it in the 100 to 150 ppm range.

Steps to Using Hydrochloric Acid to Reduce the Alkalinity of a Hot Tub:

1. Prepare the Hydrochloric Acid:

Make sure to use diluted hydrochloric acid to avoid excessive corrosion or other hazards. Wear appropriate protective gear such as gloves and goggles before doing anything.

2. Determine the Required Dosage:

Calculate the required dosage of hydrochloric acid based on the water capacity of your hot tub. According to the guidelines provided, add 0.05 gallons of hydrochloric acid for every 500 gallons of water.

3. Add Hydrochloric Acid to the Water:

Using a dropper or other appropriate tool, add the hydrochloric acid evenly to the hot tub. Make sure not to add too much at once to avoid over-acidification.

4. Stir Well:

Stir the hot tub water well to allow the hydrochloric acid and water to mix thoroughly. This may take a while, depending on how much you added and how fast you stirred.

5. Test pH and Alkalinity:

After stirring for a while, test the pH and alkalinity of the hot tub water using an appropriate test kit. Make any necessary adjustments based on the test results.

6. Adjust pH:

If the alkalinity of the hot tub has dropped, but the pH is still not in the ideal range, you may need to add additional chemicals to adjust the pH to the 100 to 150 ppm range.

Remember to be careful when handling any chemicals and follow proper safety measures. If you are unsure how to proceed, it is best to have a professional handle it.

What Is the Easiest Way to Reduce the Alkalinity of a Hot Tub?

The easiest way to reduce the alkalinity of a hot tub is to dilute it with purified water that has a low mineral content. However, this is usually not the most effective method. This is because a large amount of purified water is required for dilution. And it may take time and effort to ensure that the newly added water has the proper chemical balance.

Does Baking Soda Raise the Alkalinity in Your Hot Tub?

Baking soda (sodium bicarbonate) has a pH of 8, which is alkaline. When baking soda is added to hot tub water, it releases alkaline ions as it dissolves in the water, raising the alkalinity of the water. Many commercial pool products designed to raise alkalinity use baking soda as the primary active ingredient.

It is important to note that excessive use of baking soda may result in excessive alkalinity, which can affect the chemical balance and comfort of the water.

Does Vinegar Lower the Alkalinity in Your Hot Tub?

White vinegar is a common household item that can be used to lower the alkalinity in your hot tub. Vinegar is an acidic substance that, when added to water, can neutralize alkaline substances, thereby lowering the alkalinity of the water.

However, it is important to note that white vinegar is not specifically designed to adjust the chemical balance of hot tub water, so use it with caution. Also, make sure not to add too much white vinegar, which can cause the water to become too acidic, affecting the comfort and safety of the water.