How Long After Adding Muriatic Acid Can You Add Chlorine?

Getting your pool chemistry right is very important to you enjoying your pool. Before shocking your pool, there are some chemicals you might have to add in order to properly balance the pH and alkalinity. Muriatic acid is one of them.

Muriatic acid should be added 30 minutes to 1 hour before you add chlorine.

In this article, I will show you all you need to know about muriatic acid and how to properly administer it to your pool.

What does muriatic acid do to a pool?

First off, you hear the name muriatic acid, and you wonder what it could mean. To the uninitiated, muriatic acid is just another name for hydrochloric acid. Yeah, let’s take a trip down to chemistry class. You remember that stuff which our stomachs produce?

Do you also remember some liquid stuff in your school laboratories contained in glass jars and labeled “corrosive”? Well, chances are that one of them was hydrochloric acid.

This muriatic acid has a lot of purposes. One common one is where it is being used to reduce pH on brick walls. The pH has to be reduced so that paint can stick better.

It is not limited to that, as it also finds use in swimming pools. Muriatic acid is also used to lower pH levels in your pool, remove calcium deposits, remove rust and also clean your pool’s surfaces.

One of the most important uses of muriatic acid is for pH reduction. The pH of your pool is quite important for you to maintain sanitary levels. The ideal range for pH is between 7.2 and 7.8. It is important to get the pH right as it can greatly affect the efficacy of chlorine in your pool. If the pH of a pool goes above 7.8, the efficiency of chlorine can be reduced by over 90%. This will make your sanitizer useless.

It also helps to reduce alkalinity. Alkalinity refers to the buffering power of your pool water. In other words, it is how much acidity your pool water can resist or neutralize. The total alkalinity of your water is what helps to keep your pH in the range.

The ideal range for alkalinity is between 80 and 120 parts per million. If your pool’s alkalinity is on either side of this range, it might be hard for you to maintain your pool’s pH, especially when you start adding other chemicals. And this is where muriatic acid comes in. It helps lower the alkalinity when it goes too high.

Therefore, muriatic acid can lower both pH and alkalinity. This is how it operates. When muriatic acid dissolves in water, the hydrogen ion concentration increases. This increases acidity and lowers pH. In addition, it reacts with the bicarbonate in water, thus reducing alkalinity.

Muriatic acid can also be used for acid washing in your pool. It is possible that you are having a hard time with stubborn algae. Especially those ones that have deep roots in your pool walls, like black algae. You can use muriatic acid to thoroughly eradicate those algae. Just note that in the process, the exterior layer of concrete is usually stripped away by the acid.

How long after adding muriatic acid can you shock a pool?

The essence of adding muriatic acid to your pool is that you want to reduce the pool pH. As explained before, getting your pH into the recommended range of 7.2 to 7.8 is important for the efficiency of your shock.

With that in mind, it’s best to add the shock about 30 minutes to 1 hour after adding the muriatic acid. This is enough time for the acid to have lowered the pH of your water to the recommended range. However, it is always best to test the water before proceeding with the shock treatment. Use your test strips and ensure that your water is within that ideal range.

Do I add acid or chlorine first?

You add the acid first. Have it in mind that the goal is to reduce pH and create a condition for the chlorine to work effectively. This is how you add acid to your pool.

  1. Test the water: The first step before adding any chemical is to test the water. Even if you suspect that your water is alkaline, probably due to the cloudiness and haziness, make sure you test the water. You could make use of test strips or pH sensors that give you an overall view of the chemical balance in your pool. The major things you will be checking for will be pH and alkalinity. The pH must be in the range of 7.2 and 7.8. Alkalinity must be in the range of 80 and 120 parts per million. If the values are higher than the expected ones, you know it’s time to bring out the acid.
  2. Wear a protective kit: Remember that you are dealing with a very corrosive acid here. Even a little exposure to this acid can lead to severe burns. Ensure that your arms and legs are properly covered. Also, make sure to wear goggles. They will protect against splashes. You must also make sure that the gloves you are using are chemical and acid resistant.
  3. Dilute the acid: You must dilute the acid before proceeding. Pouring muriatic acid into your pool directly can be far too powerful. This is why you must dilute it. Remember that you pour acid into water and not the other way round when diluting. If you pour water into acid, you might cause the acid to spray around and onto you. To dilute the acid, you get about 5 gallons of water in a chemical-resistant bucket, and then you mix about 1 part of acid to 10 parts of water.
  4. Turn on the pool pump: Before adding the muriatic acid, ensure that your pool’s circulation system is turned on. This is so that the acid can circulate properly.
  5. Pour in the acid: While the pool pumps are running, you can gradually pour in the acid-water mixture. This you do by pouring it in along the perimeter as you walk around the pool. Avoid dumping it in one spot, but try to spread it evenly. In addition, pour it so that there are no splashes. Splashes from the acid can cause burns. Allow it to circulate for 30 minutes to 1 hour. This will ensure thorough mixing.
  6. Test the water again: After you have allowed the pumps to run for an hour, the next step is to test the water. You test for the pH and alkalinity levels. If it still isn’t where you want it to be, then repeat the process above til you get it right.
  7. After all this is done, you can prepare yourself to add your shock.

What happens when you mix chlorine and muriatic acid?

You should never attempt to do this. Your shock, or whatever sanitizer you are using, contains chlorine. Mixing it with muriatic acid can cause the release of chlorine gas. The release of such toxic fumes can be deadly. Chlorine is a highly irritating agent for the respiratory pathways.

It can destroy lung tissue and cause your lungs to fill with water. This will, in essence, cause death by drowning. To show how deadly chlorine is, it is used in chemical weapons. So, avoid mixing the two. As a general rule, don’t mix pool chemicals together.

How long does it take for muriatic acid to lower pH?

It can take anything from 30 minutes to an hour. However, do not enter the pool until you have properly tested the water and ascertained that the pH is in the right range.

Can I add muriatic acid directly to the pool?

Yes, you can. However, it is advisable not to do so. Muriatic acid is basically hydrogen chloride gas dissolved in water. Because of this, in its concentrated form, it can give off fumes of hydrogen chloride gas, which can be corrosive to your air pathways if inhaled. Due to this, it is best to dilute it first in a bucket before adding it to your pool. The proportion should be 1 part acid to 10 parts water.

How often should I add muriatic acid to my pool?

For proper pool maintenance, it is recommended that you add muriatic acid on a weekly basis. It is wiser to add the acid in smaller volumes at different time intervals than to add a large volume all at once. This way, you don’t run the risk of drastically reducing your pH and causing issues that can arise from a very low pH. It will also save you more and prevent your total alkalinity from being erased.

Will muriatic acid clear a cloudy pool?

When the cloudiness is due to elevated pH, muriatic acid can be used to clear that cloudiness. When calcium carbonate clouds up the pool, you can add muriatic acid to the pool water. They will react, and the cloudiness will be cleared.

What should be adjusted first alkalinity or pH?

The alkalinity should be adjusted first. The alkalinity is what helps to buffer pH. That is, it keeps your pool pH in a range and prevents it from fluctuating.

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