With summer in full swing, now is the perfect time to ensure your pool is clean and sparkling. Muriatic acid is often used to lower the pH levels of pool water, and it can be used to remove tough stains. Also known as hydrochloric acid, this substance should be used with caution, as it is highly corrosive. In this ultimate guide, we’ll show you how to safely use muriatic acid for pools so that you can enjoy a refreshing dip all season long. Let’s get started.

What Is Muriatic Acid Used For In Pools?

Muriatic acid is a very strong and corrosive chemical often used for cleaning. It can be found in many household cleaners and used in pool maintenance. It can be used to lower the pH of pool water and to remove stubborn stains from surfaces.

Follow the manufacturer’s instructions carefully when using muriatic acid and always keep it out of reach of children and pets.

Lowers pH And Alkalinity Levels

Muriatic acid lowers pool water’s total alkalinity and pool pH levels. The ideal pH level for pool water is between 7.2 and 7.6. If your pool water has a too high or too low pH, it can cause problems. Total alkalinity measures the water’s ability to resist changes in pH, and pH measures the water’s acidity or basicity. 

When pool water’s total alkalinity or pH is too high, it can lead to problems such as scale formation, cloudiness, and irritation of swimmers’ skin and eyes. Also, low pH levels can make your pool water more acidic, irritating your skin and eyes.

Cleans Cartridge Filters And D.E. Grids:

To clean cartridge filters and D.E. grids, muriatic acid removes dirt, oil, and other contaminants that can clog these components and reduce their efficiency. Also, muriatic acid can be used to clean the inside of pool pipes to remove calcium deposits and other buildups that can restrict water flow.

Removes Concrete Pool Surface Stains

Muriatic acid can be used to remove stains from concrete pool surfaces. The most common type of stain that muriatic acid is used to remove is rust, but it can also be used to remove other stains such as algae and scale. If you have a stain on your pool deck or liner, apply a small amount of diluted muriatic acid to a cloth and rub the stain gently. Be sure to rinse the area thoroughly with water after you’ve removed the stain.

Is Muriatic Acid Safe to Use?

Muriatic acid is safe if you take the necessary precautions to avoid injury. It is important to wear gloves, goggles, and a respirator when handling muriatic acid. You should also work in a well-ventilated area. When using muriatic acid, always add the acid to water – never the reverse. Doing so will help to prevent splashes and spills.

Also, remember not to mix muriatic acid with other chemicals, as this can create dangerous fumes. Finally, be sure to store muriatic acid in a safe place, out of the reach of children and pets.

How to Use Muriatic Acid In Your Pool?

To ensure your pool is clean and safe for swimming, you must test the pH levels regularly and add muriatic acid if needed. Here are steps on how you can do that:

1. Test Your Pool Water

First, you need to test the pH levels of your pool water using a reliable swimming pool water test kit. The ideal pH range for pool water is between 7.2 and 7.6. If the pH level is below 7.2, the water is too acidic, and you will need to add muriatic acid.

2. Calculate How Much Muriatic Acid to Add

The amount of muriatic acid you need to add depends on your pool size and the water’s current pH level. You can use an online calculator or ask a professional to help you determine the right amount of acid needed. The general rule of thumb is to add 1 pint (0.5 liters) of muriatic acid for every 10,000 gallons (37,854 liters) of pool water.

3. Turn Your Pump To Circulate

Before adding the muriatic acid, you must ensure your pool’s circulation system is turned on so the acid can be evenly distributed throughout the water. Also, wear gloves and protective eyewear when handling the acid.

4. Add the Muriatic Acid

To use muriatic acid in your pool, always dilute it in a bucket of water first. To do this, add water to an acid-resistant bucket first, then slowly add the acid while stirring gently with a plastic or wooden stir stick. The water to muriatic acid ratio should be 10:1, but always follow the manufacturer’s instructions.

When adding muriatic acid directly to your pool, start by pouring it into the deep end of the water. Be sure to walk away as you pour so you don’t inhale the fumes. Also, rinse your muriatic acid bucket thoroughly after each use, and don’t use it for other pool chemicals. This could cause a chemical reaction or explosion.

5. Let the Muriatic Acid Circulate

After adding the muriatic acid, let it circulate for at least an hour before swimming. This will allow the acid to distribute throughout the pool and lower the pH levels evenly. Also, keep children and pets away from the pool during this time.

6. Retest Your Pool Water

After an hour, test the pH levels of your pool water again to see if it has reached the desired range. If not, you can add more muriatic acid as needed. You should also retest the water every few days to ensure stable pH levels.

7. Aerate Your Pool

Once the desired pH level is reached, you need to aerate your pool to remove any excess acid from the water. This can be done by turning on your pool’s circulation system and letting it run for 24 hours. 

Aim your return jets upwards for best results, and set your pump to its highest setting when using muriatic acid to aerate your pool. Turn them on if you have water features like an aerator or fountain. After aerating, test the pH levels of your pool water one more time and adjust as needed.

How To Clean Your Filter with Muriatic Acid?

The water to muriatic acid ratio is usually 20:1 for cleaning cartridges or D.E. filter grids. Some steps on how to use muriatic acid for pool owners are as follows:

  • Dilute the acid with water in a clean, empty container.
  • Submerge the filter cartridge in the mixture and let it soak for at least 12 hours or overnight.
  • Remove the cartridge from the acid solution and rinse it with a hose.
  • If the cartridge is still dirty, repeat the process.
  • Once the cartridge is clean, rinse it off with plenty of water to remove any residue, and then dry it before reinstalling it.

Muriatic acid can also be used to clean D.E. filter grids. The process is similar to cleaning cartridges, except that the grids need to be soaked for 24 hours before being rinsed. It’s important to wear gloves and eye protection when working with muriatic acid.


Is Muriatic Acid The Same As Vinegar?

No, muriatic acid is not the same as vinegar. Vinegar is acetic acid, and muriatic acid is hydrochloric acid. Using the right type of acid for your pool is important because using the wrong one can damage your pool.

How Harmful Is Muriatic Acid?

Muriatic acid can be harmful if it is not used correctly. If you get muriatic acid on your skin, it can cause burns. If you breathe in muriatic acid fumes, it can irritate your lungs and throat. Therefore, you should always wear gloves and a mask when using muriatic acid.

What Does Muriatic Acid Remove?

Muriatic acid can remove calcium deposits, rust stains, and other debris from your pool. It is also used to lower the pH of your pool water. Some other benefits of using muriatic acid in your pool include preventing calcium deposits from forming on your pool surfaces and helping your chlorine work more effectively.

How Long Does Muriatic Acid Take To Lower Alkalinity?

Muriatic acid can lower the alkalinity of your pool water pretty quickly. However, you should always test your pool water before and after adding muriatic acid to ensure that you are not adding too much or too little. Adding too much muriatic acid to your pool can be dangerous. Also, dilution is key when using muriatic acid. You should always add muriatic acid to water, never the other way around.

Is Muriatic Acid The Same As Cyanuric Acid?

No, muriatic acid is not the same as cyanuric acid. Cyanuric acid is used to stabilize chlorine in pool water. Muriatic acid is used to lower the pH of pool water and remove calcium deposits and rust stains. Also, cyanuric acid is not as corrosive as muriatic acid, so it is safer to use.

Can You Pour Muriatic Acid Directly Into A Pool?

No, you should never pour muriatic acid directly into a pool. This can be extremely dangerous and can damage your pool. Always add muriatic acid to water for dilution. Follow the directions on the muriatic acid bottle for proper usage. Also, always ventilate the area using muriatic acid and never add water to muriatic acid.

How Often Should I Use Muriatic Acid in My Pool?

You should only use muriatic acid in your pool as needed. If you need to use it more than once a month, there might be something wrong with your pool water. You should test your pool water regularly and adjust the pH as needed.

When Do You Need To Use Muriatic Acid?

There are a few key instances where you’ll need to use muriatic acid for your pool.

  • The first is when you need to lower the overall pH level of the water. You’ll typically need to do this when the pH levels are high, as this can lead to scaling on the walls of your pool and make it difficult for chlorine to work effectively.
  • Another instance is when you need to clean your pool filter. Over time, dirt and debris can build up in the filter, making it less effective. Muriatic acid will help break down this build-up and restore your filter’s efficacy.
  • Also, if you have calcium deposits on the walls or floor of your pool, muriatic acid can help to remove them.


Now that you know how to use muriatic acid for pools, you can keep your pool clean and free of algae and other buildups. Just remember to use the acid safely and follow the manufacturer’s instructions. With a little care, you can enjoy your pool all season long.

We hope you enjoyed this article and found it helpful.

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Last Updated: July 28, 2022 / Categories: Outdoor & Garden, Pool & Spa / 9 min read / Tags: , /

About the Author: Brian Stilts

Brian Stilts

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