How to Safely Use Muriatic Acid in Your Pool


Maintaining the proper pH in your pool is one of the most important maintenance tasks you’ll have to do once you have a personal pool. Not only does maintaining the pH help keep the water clean and comfortable, but it’s also important for preventing unnecessary wear and tear on your pool.

The wrong pH can mean mineral deposits on the walls and floor of your pool, and can even eat into the concrete, causing thinning, and eventually, cracks and leaks. As pH rises, it can also reduce the effectiveness of your sanitation method.

Muriatic acid, also known as hydrochloric acid, is one of the most common and effective tools for maintaining proper pool pH. Let’s take a closer look at why muriatic acid is so helpful, what it’s used for, and how you can use it in your pool!

Understanding Muriatic Acid

Muriatic is one of the most common acids for lowering your pool’s pH.

Remember, acids are anything with a pH between 0-7, while alkaline bases are between 7-14. A pH of 7 is true neutral.

Your pool should stay somewhere between 7.2 and 7.8, which is very slightly basic. But it’s relatively common for pools to become too basic, with a pH higher than 7.8, which is when acids like muriatic acid come in.

When you need to lower the pH of your pool, muriatic acid is one of the fastest-acting options. It’s also one of the most affordable chemicals for quickly lowering the pH of the pool. Those two features mean that it’s one of the most popular maintenance chemicals.

However, it’s also important to remember that one of the reasons that this acid is so effective for changing pool pH is that it’s a very strong acid. That means that it’s incredibly important to make sure you’re using proper protection and are cautious and careful when you’re working with muriatic acid.

If you are worried that you might not be able to handle muriatic acid safely, it’s probably better to wait until you’re better able to work with it or to consider getting a pool maintenance service so you don’t have the mess with the acid and other chemicals yourself.

Safety Precautions

Staying safe while using muriatic acid means taking some precautions to minimize the risk that you will get some acid on you. Remember that muriatic acid can also eat through concrete and many other substances as well. If you spill any you should clean it up as quickly as possible, without risking getting any on yourself.

It’s important to wear protective gear when you’re working with muriatic acid. That includes long sleeves and pants, gloves, goggles, preferably all waterproof and acid-resistant. The goggles are particularly important, and safety glasses are not a replacement. Muriatic acid vapors can burn your eyes and are also irritating to your respiratory tract.

You should also avoid breathing muriatic acid fumes. A respirator is a good idea if you can, and even with a respirator on you should only work with muriatic acid in a well-ventilated area.

It’s also important to think about how you’re going to store muriatic acid, since it should be in a spill-proof container, somewhere stable where it is unlikely to spill, ideally somewhere that is both dark and temperature controlled.

In case of an emergency, you should have both plain water and baking soda on hand. The baking soda helps neutralize the acid, while the water can help you wash the acid off. Apply baking soda first when possible.

If acid gets into your eyes or on your skin, rinse the area thoroughly and seek immediate medical attention if you have any discomfort or other symptoms.

It is also a good idea to have someone else around if you are working with muriatic acid. That way they can help deal with any potential problems, including contacting medical services if they are needed.

With the right precautions working with Muriatic acid can be perfectly safe. You just need to make sure you’re prepared before you get started.

Testing Pool Chemistry

Before you make any adjustments to your pool, including adding muriatic acid or any other chemicals, it’s important to test pool chemistry so you know which adjustments are needed.

While you can start to get a sense of what your pool needs, and when it needs it, it’s important to remember that only a test is going to definitively tell you what to do.

Especially when your goal is to change the pH of your pool, it’s important to test both pH and alkalinity before making adjustments. Remember that pH is a measure of how basic or acidic your pool is, while alkalinity tests how much the water will resist acidification.

Both are important to determining how much muriatic acid to use and even whether you need muriatic acid at all.

The easiest way to test your pool chemistry is to use a reliable pool water test kit, especially if you’re testing multiple parameters at once.

It’s also a good idea to test the water again several hours after making any adjustments before anyone swims in the pool. That way you can see if the adjustments were successful, if you need to add more of anything, or if the pool is trending in the right direction but still needs some time for the added chemicals to work.

Remember, even with the pool filter working at water flowing, it can take time for your pool to adjust and for muriatic acid and other chemicals to do their job.

Determining the Amount Needed

It’s important to figure out the precise amount of muriatic acid you need to add to your pool, like any pool maintenance chemical. To do that, first, you need to know what the pH of your pool is, as well as how big it is and how much water you’re working with.

The best way to calculate the volume of water is a simple equation: Length x width x average depth x 7.5 = gallons of water. You’ll also need to test the pH of your pool and remember that you want your pool to be somewhere between 7.4-7.6 pH. Alkalinity should be around 100-150 ppm (parts per million), and the closer to 125 ppm the better.

Once you know how much water is in your pool, and the pH of the pool (assuming normal alkalinity), you need to figure out how much acid is needed.

You can use an online calculator to determine the amount of acid needed. Remember that the amounts are an estimate, and it’s always important to let the water circulate for a few hours and then double-check your results.

Application Methods

There are two options when it comes to adding muriatic acid to your pool. One, broadcasting, involves adding the acid by broadcasting it over the area of the pool, which helps the acid dilute directly in the pool water.

Remember that getting the acid to mix into the water is key, both to change the pH, and to keep the pool safe to swim in, and prevent damage to the concrete lining the pool and other pool equipment. Muriatic acid is heavier than most pool water, which means that the acid is prone to sinking to the bottom of the pool without mixing in.

Broadcasting is generally less popular, partially because high-concentration muriatic acid is more dangerous to work with, and because it’s hard to get enough distribution to really protect your pool. However, in pools with good flow and lots of movement, it can be an option.

Pre-dilution is an alternative that can help muriatic acid mix into your pool since it’s already mixed with water and not quite as heavy. Mixing is still important with diluted muriatic acid, but the risks of damaging the pool or getting a high-acidification zone are lower.

The ideal ratio for pre-dilution is 10:1 water to muriatic acid. Most pool owners use a 5-gallon bucket of water for diluting muriatic acid. It’s important to make sure you add the water first and then add the muriatic acid.

If you don’t have enough room for the right ratio in a single bucket, you can mix more than one bucket worth to add in.

With both pre-dilution and broadcasting, it’s important to add the acid in a high-flow area, or in the deepest portion of your pool. Either option makes it easier for the acid to mix with the water and helps protect your pool and the concrete at the bottom.

Step-by-Step Instructions

We’ve already gone over most of the process, but here is a quick step-by-step guide so you know exactly what to do.

  • Test Pool pH

First, get your pool test kit and figure out the pH of your pool. Depending on the reading you get, you might want to test multiple areas of the pool.

  • Calculate Necessary Muriatic Acid

Length x width x average depth x 7.5 = gallons of water. Then use the pH of the pool and an online calculator to figure out how much muriatic acid is needed to get your pH into the ideal range.

  • Get Protective Equipment

Before you get any chemicals, make sure you have your protective equipment and clothing, water, and baking soda, and are ready to go. Make sure you have acid-resistant gloves and air-tight goggles at a minimum, and check the seal on your goggles.

  • Make Sure The Pool Is On

Your pool needs to be circulating water when you add muriatic acid. Make sure the pool is one and check the vents.

  • Dilute The Required Acid OR Measure The Required Amount

Measure the amount of muriatic acid you calculated earlier. Either broadcast that into your pool or use a 5-gallon plastic bucket to dilute the muriatic acid before adding.

  • Pour The Muriatic Acid Solution In

Add the muriatic acid to your pool, watching to make sure it mixes in properly.

  • Wait and Re-Test

Wait several hours (2-6, and longer is better) and retest the pool. Make additional adjustments as needed, using the same process.

Testing and Monitoring

Like a lot of things in real-world chemistry, you can’t control how the chemical interacts with your pool 100%. Testing and re-testing your pool chemistry is the only way to know that you’ve made the right adjustments and gotten the results you’re looking for.

Regular testing and long-term maintenance can help make it easier to avoid significant chemistry problems. But, you should make sure to test pool chemistry after weather, especially if you got a lot of precipitation or a lot of debris fell into your pool since rainwater and debris can affect pool pH and chemistry.

Clean-up and Disposal

You shouldn’t rinse muriatic acid containers or wash them down the drain. Remember, muriatic acid can eat through most materials and can cause some significant damage to your plumbing or the sewer system it leads to.

Instead, take empty muriatic acid containers, leftover muriatic acid solutions, and any containers you’ve mixed muriatic acid solutions in, to a hazardous waste disposal facility when it’s time to get rid of them.


Maintaining your pool can quickly become a routine task, but that doesn’t mean you can cut corners or skip safety precautions. Remember that muriatic acid never gets less dangerous, even and especially when you get used to working with it.

Remember to keep your safety precautions in place and to make sure you’re being careful when you’re working with muriatic acid, no matter how safe and normal it feels.

Staying up to date on your pool maintenance makes it a lot easier and can help reduce how much muriatic acid you need to use when you’re making adjustments.

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