How To Lower Alkalinity in Pool: Treating High Levels of Alkalinity in Your Swimming Pool

In this pool care guide, you're going to learn how to lower the alkalinity in your pool (FAST).

To lower the alkalinity in your pool, try using a strong acid like muriatic acid, sodium bisulfate, or sulfuric acid all of which will lower the alkalinity.

If your pool water is a little murky or your pool filters seem to be plugged with calcium deposits, then your pool may be suffering from high alkalinity levels. To be sure, you can always test the total alkalinity levels in the pool water with test strips.

In today's post, you're going to learn all about water alkalinity, what causes your pool alkalinity to get too high, and how to lower your swimming pools alkalinity.

Let's dive in!

What is pool water alkalinity?

Not to worry.

High alkalinity in your swimming pool is totally curable if you know what to look for in the water.

Water alkalinity is a “measure of how much acid it can neutralize.”

In the swimming pool, it acts as sort of a buffer to stabilize pH levels, which is important to prevent scaling and other pool problems.

Pool alkalinity is measured at total alkalinity (TA) and it is simply the amount of alkaline substances in the water. 

In a swimming pool, the bicarbonate alkalinity is the substance that needs to be regulated.

The total alkalinity level should be between 80 and 120 ppm (parts per million).

By the way, this total alkalinity also applies to hot tubs (if you want to lower the alkalinity in your hot tub).

Why you need to lower alkalinity

In The Swim Alkalinity Increaser for Swimming Pools - Raises Alkalinity and Balances pH Levels in Your Swimming Pool Water - 100% Sodium Bicarbonate - 25 Pounds
  • In Swim Alkalinity Increaser maintains pH and chlorine levels.
  • Prevents pH swings, maintaining stable water chemistry.

An alkalinity level that is too high in a swimming pool can lead to problems such as an imbalanced pH level, which contributes to high calcium levels in the water.

High calcium levels can cause scaling, cloudy water and clogged filters in your pool.

Not to mention, itchy skin and irritated eyes for your swimmers!

What causes high swimming pool alkalinity?

One of the main reasons pool alkalinity can get too high is when you have added too much sodium bicarbonate (baking soda) to the water when you were trying to raise the total alkalinity amount.

Yes, alkalinity that is too low is also a problem for your pool water, but we will save that discussion for another day!

To keep high alkalinity from happening too often, use smaller increments of the chemical when adjusting alkalinity levels and test the water every 24 hours until it reaches its ideal conditions.

Another factor that often causes alkalinity levels to get too high is your pool water source.

Water companies are required to disclose their water testing results to its consumers, so a quick call to the company will help you determine what chemicals you regularly need to keep your water balanced.

Taking accurate readings of alkalinity in swimming pools

You should test your pool’s alkalinity levels every time you test your other pool chemical levels, but if you have noticed some signs of high alkalinity in the water, it’s certainly okay to go ahead and test those levels more often.

You most likely have already bought a pool water testing kit and it should contain the reagents necessary to test the pool alkalinity levels.

If for some reason, you find yourself without this, you can buy some alkalinity test strips separately. However, test strips are not quite as accurate at determining high alkalinity levels.

Once you’ve gotten out your vial and reagent for testing, collect a sample of pool water about 12” below the surface. Then drop the reagents slowly into the water sample and use the manufacturer’s directions to determine your reading.

Total alkalinity levels in your pool should always be between 80-120 ppm.

What is the fastest way to lower alkalinity and adjust pH in a pool?

The quickest and most effective method to reduce the alkalinity level in a swimming pool is by adding an acid, such as muriatic acid or sodium bisulfate. These chemicals work by lowering the pH levels in the water, subsequently reducing the alkalinity level. Here's a step-by-step guide on how to lower alkalinity in pool water:

  1. Test the water: Begin by testing the pool's water to determine the current pH and alkalinity levels. This will help you understand the required dosage of acid to add to the pool.
  2. Choose an acid: Muriatic acid and sodium bisulfate are popular choices for lowering swimming pool alkalinity. Muriatic acid is stronger and faster-acting, but sodium bisulfate is safer to handle and store.
  3. Calculate the dosage: Use a pool calculator or consult the manufacturer's guidelines to determine the correct amount of acid needed to lower the alkalinity to the desired level. Always err on the side of caution and start with a lower dosage, as you can always add more to the swimming pool if needed.
  4. Apply the acid: To ensure even distribution of the acid, pour the acid in a thin stream around the perimeter of the pool while the water pump is running. Be cautious while handling the acid and wear protective equipment, such as gloves and goggles.
  5. Monitor the water: Allow the pool's circulation system to run for at least four hours after adding acid to the water. Then, retest the pH and alkalinity levels. If the alkalinity level in the water is still high, repeat the process with a smaller dose of acid.
    Remember, it is essential to maintain proper water and pH balance in a pool. Regular testing and adjustments will help you keep the alkalinity, pH, and other water parameters within the recommended ranges, ensuring a safe and enjoyable swimming experience.

How to lower alkalinity with muriatic acid

Pool Mate 1-2256B Alkalinity Increaser for Swimming Pools, 10-Pounds
  • Sodium bicarbonate for pools
  • Raises total alkalinity and helps keep pool water pH stable

There are a few chemicals you can use to lower your pool’s alkalinity level, but muriatic acid is the most common chemical for adjusting the water pH level.

In order to lower the alkalinity levels, just follow these easy steps to add muriatic acid to your swimming pool:

  • 1
    Turn off your swimming pool’s pump and wait about an hour for the water to stop moving completely.
  • 2
    Read the directions on the bottle of acid to determine how much acid needs to be added to your pool in order to lower it to under 120 ppm.
  • 3
    Follow the manufacturer’s directions on how to add the acid to your pool. Muriatic acid is always somewhat diluted, but certain brands require further dilution before adding it to the water in your pool.
  • 4
    Pour the acid into the deepest part of your pool and allow it to sit in still water for about an hour.
  • 5
    Turn your pool’s pump back on and let it run for at least 5 hours.
  • 6
    Test the total alkalinity again in the water.
  • 7
    Test the swimming pool pH levels.

The problem with unbalanced alkalinity levels is mainly how it affects the pH levels in the swimming pool water.

If your pool’s pH levels are still low (under 7), you may have to use an aeration process along with adding muriatic acid to stabilize the pH level.

I only recommend this process in extreme situations where you are unable to lower the pH levels naturally after using the muriatic acid process more than once.

Usually, leaving the pool’s pump running on high is enough of an aeration process, but if an extra process is necessary, you can use a compressor at the surface of the water or use a special aerator to insert into the pool.

If you attempt this process, do it slowly and carefully as you can also risk over-aerating the water. 

Lowering your pool’s alkalinity levels is sometimes a slow process.

You may have to repeat the entire process after a few days if the total alkalinity levels have still not dropped to the appropriate reading.

You will also want to make sure to test your pH and chlorine levels after a few days so that you can balance them all as needed. Use pool test strips and other testing equipment to get accurate readings.

How do I lower the alkalinity in my pool naturally?

If you're looking for natural methods to lower the alkalinity in your swimming pool, there are a few eco-friendly alternatives you can consider for addressing high alkalinity. Although these methods may take longer to show results compared to using chemicals, they can be a more sustainable option for your pool maintenance routine.

Aerate the water: Aeration is an excellent way to lower alkalinity levels naturally in your pool. It involves increasing the water's exposure to air, which raises the pH levels and decreases the alkalinity. To do this, you can use a pool fountain, water feature, or an air compressor. Direct the water flow upward to maximize air exposure, and run the aeration system for a few hours each day until you reach the desired alkalinity level.

Add vinegar: White vinegar, a mild acid, can help lower alkalinity in your pool. To use this method to lower total alkalinity, calculate the amount needed to reduce the alkalinity to the desired level. Slowly pour the vinegar around the pool's perimeter while the pump is running to ensure even distribution in the water. Monitor the alkalinity levels and adjust the vinegar dosage as needed. Keep in mind that using vinegar may not be as effective as stronger acids, and it may take longer to decrease the total alkalinity in the pool.

Balance the pH levels: Maintaining the pH levels within the recommended range of 7.4 to 7.6 can indirectly help in managing the alkalinity of your pool. If your pool water has a high pH, use natural pH reducers such as citric acid or vinegar to bring it back to the optimal range.

While natural methods may be slower and less efficient than using chemicals, they can still be effective in maintaining the health and balance of your pool water. Remember to test your pool's water frequently and adjust your maintenance routine as needed to ensure a safe and enjoyable swimming experience.

FAQ on Alkalinity in Pools

Hopefully at this point, your pool’s alkalinity levels are back within normal range, but you might still have a few common questions regarding the process of lowering alkalinity in pools.

Here are some of the ones I hear a lot about how to lower pool total alkalinity levels:

How do you lower alkalinity without affecting the pool’s pH level?

It’s tricky to lower your pool’s alkalinity without in turn lowering the pH levels, but it can be done.

Here is a good step-by-step tutorial to follow when lowering total alkalinity without impacting the pH level.

Can you swim in a pool with high alkalinity?

High alkalinity itself is not necessarily an unsafe swimming condition.

It can, however, cause some water issues that could potentially make it unsafe, such as:

  • Decreased chlorine effectiveness
  • Cloudy water
  • Unstable pH levels

In other words, use caution in pools with high total alkalinity.

It’s better to go ahead and stay on top of keeping your pool’s levels balanced than to risk unsafe or unclean water.

Can you use baking soda to lower alkalinity?

Sodium bicarbonate, aka baking soda, is a chemical you can use to raise your pool’s alkalinity.

However, muriatic acid is the best chemical to use in order to lower the alkalinity levels in your swimming pool. 

Bottom line on pool alkalinity levels

Low alkalinity is a more common problem than high alkalinity, but either problem can cause an imbalance in your pool’s chemistry.

It’s always best to use good testing equipment to test all your pool water levels at least once a week as having any one of the levels off-balance can cause serious issues for your pool and your swimmers.

Remember the process of lowering pool water alkalinity may take longer than balancing the other levels.

Just be patient when lowering total alkalinity and keep testing the water!

And once you lower the total alkalinity of your swimming pool and your water reaches ideal conditions, do your best to keep it there. Your job will be much simpler in the long run!

Scroll to Top
Scroll to Top