Swiming Pool, Swimming FAQs

How Much Muriatic Acid To Add To A Swimming Pool?

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So now you’re prepared to add muriatic acid to your pool. How much acid do you really need, though?

The quantity required, however, will vary depending on a number of variables, including your pool’s size, the volume of water in it, and the pH balancing system you use.

In this article, I’ll explain the kind of system you have and how much muriatic acid you should add to get it to a specific, healthy pH level.

Muriatic Acid Definition

Muriatic acid is a special type of acid that’s considered to be a less-pure and somewhat diluted version of hydrochloric acid. The fact that this acid is extremely corrosive makes it useful. Muriatic acid, for example, can corrode anything from carpet and clothing to metals and plastics. As a result, it is successful in lowering the pH of water. However, muriatic acid’s corrosive properties are also what make it risky to use if you don’t know what you’re doing. Severe burns will result from this acid getting on your skin.

Why Would You Add Muriatic Acid To A Swimming Pool?

Alkalinity in swimming pools is reduced using muriatic acid. You can lower pH by lowering alkalinity. High pH levels can harm your filtration system and render your pool’s chlorine ineffective.

High pH can make the filter, pump, and heater work harder, which can all result in long-term damage.

Your pool will be more acidic if its pH reading is lower.  More alkaline or basic water is indicated by a higher pH in the pool. Above a pH of 7.4, chlorine is less effective at sanitizing the water because it promotes bacterial growth, which can irritate the skin and eyes.

The other chemical reactions going on in a pool can suffer when the pH is out of whack, which can lead to issues like cloudy water, scaling, or corrosion.

Why Do Pools Use Muriatic Acid?

Muriatic acid is helpful for lowering high alkalinity and pH levels in your water, cleaning cartridge filters, or D.E. grids, and removing pool surface stains.

Lowers Total Alkalinity And Ph

By reducing the total alkalinity and pH levels in your pool, muriatic acid can help balance the chemistry of your water. Since alkalinity and pH are interdependent, it will probably result in a simultaneous decrease in both levels. However, they could diminish at various rates.

Why is that? Because your water’s pH is naturally unstable, alkalinity acts as a “buffer” to help keep it from changing too drastically and quickly. As a result, it will aid in bringing down your pH to the proper range as your total alkalinity returns to normal (for example, after adding muriatic acid).

Check out our article on Basic Pool Chemistry 101 if you’re unclear about the chemistry of this type of pool water.

So why is it problematic to have high pH and alkalinity? Your water may become cloudy and your chlorine treatment may not be as effective if your pH is too high. A risk of algae blooms results from chlorine that is less effective. Scaling brought on by high pH can harm your filter system. Between 7.4 and 7.6 is the ideal pH range for you.

Similar to how too much total alkalinity can lead to scale buildup in your pool and filter system. Additionally, it might raise your pH levels along with it, messing up the balance of your water’s chemistry. Your alkalinity levels should be 125 ppm or higher, which falls within the range of 100 to 150 ppm.

Now it’s important to note that high alkalinity levels will naturally decrease over time on their own. However, a high total alkalinity can cause other problems, such as a high pH and ineffective chlorine, which can result in algae. Therefore, it often pays to deal with high alkalinity levels before they can lead to bigger problems.

Filters For Cartridges And D.E. Grids

If your swimming pool has a cartridge filter or a D.E. filter, you may already have muriatic acid on hand. It’s frequently used to thoroughly clean cartridge filters, and it’s especially helpful for dissolving the sticky residue that accumulates in the pleats.

Diatomaceous earth, or D.E., can be thoroughly cleaned with muriatic acid as well. filter grids (or fingers if you have a The pores of the grid can become clogged with calcium scale deposits, but soaking the grid in a muriatic acid solution can help dissolve any buildup.

The final section of this article explains how to clean your filters with muriatic acid.

Removes Concrete Pool Surface Stains

Muriatic acid is a potent stain remover as well. It can clean the grout between your swimming pool tiles, remove rust stains from your pool’s surfaces, and resurface your concrete pool deck.

However, as effective as it is in removing old, stubborn pool stains, it can be too harsh. Inadvertent corrosion and plaster discoloration can result from the use of acid. Therefore, test it out on smaller pool surface areas first. On your concrete deck, never leave a jug of muriatic acid out: it could leave a ring!

By the way, if you’re feeling confused or overwhelmed by pool maintenance, check out our pool maintenance video course. Everything you require to keep your pool clear and clean is covered in this simple-to-follow guide.

Swimming Pool

Adding Muriatic Acid All At Once Is Possible?

It’s best to add muriatic acid gradually rather than all at once. Muriatic acid should be added to your pool gradually, after first being diluted in a bucket. You can safely and gradually add the acid in this manner.

There is a lot of bad information online that says it’s okay to pour muriatic acid (also known as hydrochloric acid or HCL) straight out of the bottle as long as you walk around your pool while you’re doing it, but this is terrible advice. Always dilute your acid before using it. As you add it this way, you can check your pH to make sure you’re not adding too much and add it gradually.

How Much Muriatic Acid Should I Put In My Pool?

Both the size of the pool and the pH level of your pool play a role in this. When using test strips, it can be challenging to pinpoint exactly how high the pH level is; you simply know it is high. A better test kit, or a DPD drop test kit, will use phenol red to give you a more accurate indication of your true pH reading. In order to determine a dosage more precisely, some better test kits also include an “acid demand” test.

If your in-ground pool is an average size (15,000 gallons) and your pH reading is 7.8 or higher, you should add 1/4 gallon (a quart) of muriatic acid and retest an hour later. You should start with one cup of acid if you have a smaller pool or an above-ground pool, then retest and add more if necessary. We are only referring to capfuls if you have a spa. pH adjustments in spas only require a small amount of acid.

See the table below for a more precise idea of how much acid to add, or use a pool calculator you can find online to get an estimate based on the chemistry and estimated volume of your pool.

Steps To Add Muriatic Acid To Your Pool

You might need to add some muriatic acid to lower the pH levels if you think the water chemistry in your pool isn’t properly balanced. It is advised that you carefully read the following instructions regarding how to add muriatic acid to the pool before you proceed. You ought to be able to add the acid safely if you stick to these instructions. If you require any help, get in touch with Sensorex.

Step 1. Test Your Pool’s Levels

The first step in this process involves testing the water chemistry levels in your pool, which can be done with several different test strips that can be used to determine the pH levels of the water in your pool, these strips may not be accurate. Use a pH sensor instead, which can deliver accurate pH readings. At Sensorex, we provide a broad selection of pH sensors, from differential pH sensors that can withstand rigorous testing to laboratory sensors that are perfect for pool testing.

If you plan on testing the water chemistry of your pool on a regular basis, you might want to opt for a process sensor or differential sensor. The pH1000 sensor, which is dependable and simple to use, is a fantastic pH sensor for swimming pools. If you intend to use the sensor for a variety of applications, the SD7420CD probe can also be very useful. If you notice that the pH readings are excessively high, it might be time to add some muriatic acid to the pool. Keeping in mind that the ideal range for pool water is between 7.2 and 7.8, anything higher may necessitate the addition of acid.

Step 2. Wear Protective Gear

Before you start adding muriatic acid to your pool, it’s very important that you wear protective gear. Even momentary exposure to the skin can lead to the development of severe burns in the affected areas, which is why protective gear is essential. Make sure your clothing can completely cover your legs and arms before you start adding muriatic acid to the pool.

Use goggles if you have them to shield your eyes from any possible splashing. You should also make sure that you are wearing sturdy, acid-resistant gloves. You should be able to find the gloves’ resistance information on their label. If any acid spills on your skin, you should apply cool water to the area right away to lessen the acid’s effects.

Step 3. Dilute The Acid

The next and most crucial step in adding acid safely to your pool is diluting the acid. If you add acid to your pool water without first diluting it, the solution will be far too potent. Before adding acid to the pool water, the acid can be diluted to achieve the proper chemistry.

Make sure that you never add water to acid before you begin diluted the acid. The acid will spray onto you as a result of the strong reaction that results from doing this. Fill a 4-5 gallon bucket with water before beginning to properly dilute acid. As opposed to pool water, this water ought to be clean. One-tenth of one percent, or about 10% of the water in the bucket, should be acid.

Step 4. Turn On Your Pool

Prior to adding the acid to the water, be sure to turn on your pool. The water should be running and circulating fully before you place the acid in the pool.

Step 5. Slowly Add The Acid To The Water

Now it’s time to finally add the acid to the water. You should walk around the pool’s perimeter with your prepared acid/water mixture so that it can evenly distribute throughout the entire pool. You must wait at least 30 minutes before entering the pool again. It is advised that you pour in the acid into the water very gradually. Extra precautions are necessary because splashes could result in burned skin.

Step 6. Check The PH Levels Again

Now that you’ve added the muriatic acid to your pool, it’s time to check the pH levels again. Do not forget that this testing should only take place after a few hours. You can add very small amounts of muriatic acid to the pool water until you reach the desired pH if the sensor readings are still too high. Make sure that you retest the water every 3-4 hours until you have reached the correct pH readings, which can be anywhere from 7.2-7.8.

The pH3000 research-grade sensor, the SD4720CD probe, and the pH1000 lab sensor are among the various pH sensors that can be used to test the water, as was already mentioned. All of these sensors will give you accurate readings that can help you decide whether to add more muriatic acid to the pool water.

How Often Do I Use Muriatic Acid In My Pool?

The type of pool, the kind of chemicals being used, the pH level, and other variables all affect the answer to this question.

Muriatic acid can typically be used once every two weeks in a chemical-free pool. Your pool may need to be used more frequently if it uses chlorine.

Your tap water’s pH level is another crucial consideration. For an algaecide to be effective, the pH level must be lower than 7. Since it won’t be able to dissolve the cell walls of algae or stain cells if the pH level is above 7, it will not function as an algaecide or stain remover.

How Safe Is It To Use Muriatic Acid?

Muriatic acid is a very practical and reasonably priced pool maintenance tool when used properly. But because it’s an acid, it’s crucial to adhere to a few safety precautions:

  • Always wear face protection, including a respirator, acid-resistant gloves, eye protection, and fully-covering clothing. Keep in mind that if this highly corrosive acid or its fumes come into contact with your body, they could cause harm to your skin, lungs, and eyes.
  • Dilute your muriatic acid in water for the safest application. This entails carefully and gradually adding muriatic acid to a bucket that is already filled with water. Never add water to acid because doing so could splash the acid on you. Additionally, always use a plastic container that can withstand acid.
  • Store muriatic acid in the container that it came in. Furthermore, keep it far away from other acids and pool chemicals. Never mix chemicals together!
  • Keep a hose or water source nearby to wash your skin in case you accidentally splash yourself. And to quickly neutralize any acid, use baking soda.

How To Safely Add Muriatic Acid To A Swimming Pool?

To make sure you really need to add chemicals, you should test the water before doing so. You have a few options for testing the water: test strips, a good liquid test kit, or bringing a sample to your neighborhood pool shop.

In order to add muriatic acid to your pool, you must first calculate the appropriate amount. The section titled “How Much Muriatic Acid Is Needed” has more information on this.

Muriatic acid must be diluted in a bucket of water in order to be added safely.

Wear chemical-resistant gloves, an apron, goggles, and if you have them, a chemical-resistant mask to complete this safely.

Then, fill the bucket with 10 parts water and 1 part muriatic acid. Muriatic acid should be added after the water has been added. To prevent splashing, mix the acid with water first.

If you have extra muriatic acid, you can either save it for later use or read our blog post on how to get rid of leftover muriatic acid.

How Long To Swim After Muriatic Acid

It is always advised to carefully read and adhere to the directions provided on the product label, regardless of the type of pool chemical you are using. This label will have useful safety and handling instructions, such as suggested intervals between swimming sessions. In general, the following recommendations apply to most swimming pools:

After Adding pH, Alkalinity and Clarifier

The addition of water balancing chemicals should be given at least 20 to an hour of time to work.

After Adding Calcium Chloride to Raise Calcium Hardness

After adding calcium chloride to your pool, you should wait two to four hours (or a complete filter cycle) before going swimming.

After Shocking Your Pool

Once your chlorine levels are around 5 ppm or after 24 hours, it is safe to swim. It is best to test first, always!

After Adding Muriatic Acid

Muriatic acid has the potential to produce a hot spot of acid in the water that could burn or irritate your skin. It is best to wait 30 minutes after adding it to your pool.

After Adding Algaecide

After putting algaecide in your pool, we advise waiting at least 15 minutes before swimming. The majority of algaecides are completely safe to use while swimming.

After Adding Floc

Swimming in your pool while using flocculant is not advised because it will lessen the substance’s effectiveness. Only swim once the floc has accumulated at the pool’s bottom and been removed by a vacuum.

Liquid Chlorine

It is generally safe to hold off adding more liquid chlorine for 4 hours or until levels are 5 ppm or lower, depending on how much you have added and the size of your pool.


In conclusion, you shouldn’t pour in too much or too little muriatic acid. Prior to slowly adding it into their pool, it is preferable to dilute it in a bucket of water. To do this, calculate the required amount of acid based on the alkalinity and pool size currently in use.