How To Lower Alkalinity In Pool

Does your pool water look cloudy? Do you notice any scaling on the filter or other pool accessories? Or your pressure readings are suddenly high? If you notice all of these you should know that they are all signs which show that pool alkalinity is high.

Why should you lower alkalinity levels?

You should invest some time to lower it because it damages pool equipment such as pump motor, filter pump and flow of the water in the pipes. In addition to this, if you want to take a swim in the water, you will experience skin irritation, your hair and skin will feel as though they are sticky and you will feel like your eyes are burning. Here are some more effects of high alkalinity in pool water:

  • It causes scale deposits on the walls, equipment and plumbing
  • If you leave it high for a long time, it may take weeks to return to normal
  • It can cause problems with pH levels as well
  • You may risk facing a maintenance bill that can cost thousands of dollars.

How to lower alkalinity levels

In order to do this, you must first know what is the size of your pool, especially the volume of it, because it will determine how much chemicals you have to use. You will be pleased to know that you do not have to spend a lot of money to lower the volume, you just need to have patience and ensure that it does not happen again if you want to have the pool for many years to come. Usually, the experts recommend that the level should be between 80 and 120 ppm whereas if you have a pool that is made out of plaster, you should keep the total alkalinity around 100 to 125 ppm.

The very first thing you need to do is take a test or accurate readings of your alkalinity levels because the numbers will guide you to the right amount of chemicals to be used to level the playing field. Then, you should decide what you want the level to be, it all depends on the size of your pool. After you have done the readings, you have to decide what chemical you want to use. There are two most efficient chemicals and these are Muriatic Acid and Sodium Bisulfate (also known as dry acid).

How to use Muriatic Acid

This is one of the most reliable products because it has many uses. Having it handy in your home will benefit in many ways because you can use it for household cleaning, descaling and cleaning brickwork. Here are the instructions we advise you to follow:

  • Pause the pool pump from functioning and allow extra 45 minutes to ensure that water stops circulating
  • Depending on the water volume you can either dilute it or add it directly to your pool. Here is the trick, if you have a deep pool you should add it to the deepest part. If not, pour it into different areas to ensure that the flow carries the product all over the swimming pool floor
  • Leave the acid to work its magic for about an hour then turn on the pool pump
  • We advise you to check 6 hours after to make sure that there was a reaction, then come back again after 24h to make sure that you have given the water enough time to adjust
  • Come back again 48 hours later and check your final readings and if you are not happy with the results, repeat the entire process until you get your desired results
  • Check the pH levels because the process may lower that level as well

How to use Sodium Bisulfate

This is another product which you should definitely have in your home. It is also called dry acid because it comes as powder or granular. You may be surprised that you can find it in dietary supplements and a range of antifungal creams. Below are the rules which you should follow in order to lower the alkalinity levels:

  • Turn off the water pump and give it around 45 minutes to ensure that the water is completely still
  • It’s important that you read the product’s label and you know the water volume because it will determine how much powder you should use
  • Dilute the product in a container
  • If you have a diving pool, pour the mixture in the deepest part of the pool or in different areas so you ensure that the stream will take the product all over the floor of the pool
  • Leave it to work its magic for one hour then switch back the pool pump
  • Come back and check the readings after 6 hours
  • If the alkalinity levels haven’t gone down after two days, repeat the process again


All that you need during this process is patience, the more you have of it, the better it is. We understand that it can be frustrating because you may just want a quick swim but you need to realize how dangerous it is for you or the people you love.

Extra tip to use

If adding chemicals to your swimming pool does not appeal to you, there is another method which you can try. It is called aeration. What you have to do is allow the water in the pool to get more air or carbon dioxide, if you want to be precise. Nonetheless, even if it works you must understand that by doing this you will raise the pH levels and it may take a long period of time to bring down the alkalinity levels. Here are the rules you should follow in order to be efficient:

  • Place an air compressor at the surface of the water
  • Make sure that the product has numerous tiny holes at the end because it will speed up the process
  • Put it in the deepest end to ensure that the whole pool gets aired out. You will notice small bubbles coming out of the tube and they are the ones which produce the carbon dioxide the water needs
  • Let the pump pressure running on a high level
  • You may also use a pressure washer pointed at the water to create rough air currents
  • Do this method until you get the reading that you want

To wrap this up

There are several key points which you must first understand in order to get to work. To begin with, you need to understand that if you leave the alkalinity levels high, it will be a danger to your skin and efficiency of pool equipment. Furthermore, you need to purchase a reliable test kit to provide you with reliable readings because you need to know the exact measurements of how much chemicals to use. If you do not want to spend a long time to see results, we advise you that you use the chemicals we have highlighted above. Even if you do not get the results you want from the beginning, try the process again because with patience you will get it right eventually.

Frequently Asked Questions

1 Can you explain in simple terms how to lower alkalinity in a swimming pool?
The success of lowering alkalinity in your swimming pool, strongly depends on the acid you use. According to several specialists, the muriatic acid is one of the most reliable and efficient products. It works fast and it does a great job. Also, you can use Sodium Bisulfate. It has the same effects as the muriatic acid.

2 How to test the pool water for hardness?
You can test a swimming pool water for hardness in various ways, but the most common way is to use a test strip. You just have to dip the test 18 inches below the water and remove it when the color changes. The purpose of this test is to indicate the hardness level. The ideal levels are between 200 and 400 ppm.

3 What are the recommended levels for chlorine?
The optimum level for chlorine is between 1.0 and 2.0 ppm.

Comments are closed.