A muriatic acid is a diluted form (14.5-29%) of hydrochloric acid, which is widely used for different home projects for restoration and maintenance. It is also commonly used for various industries such as leather workers, pearl makers, and others.
It is an inexpensive cleaning and maintenance agent readily available on the market, but at the same time, it is a potent chemical that can be hazardous if not used properly.
Since it is a caustic acid that is capable of corroding just about anything, muriatic acid can cause severe burns to the skin, nose lining and lungs, and can cause permanent eye damage and blindness if it comes into contact or if inhaled.
So, our recommendation is to use the muriatic acid with all precautions in mind and as a last resort rather than as a regular detergent for cleaning and maintenance.
Read on to find out more about what muriatic acid can be used for and, more importantly, how to use it safely around the house.
Muriatic Acid vs. Hydrochloric Acid
As mentioned earlier, muriatic acid is a diluted form of hydrochloric acid. Usually, it is less pure than hydrochloric acid and has been diluted to 14.5 to 29% of acid. Some of the impurities which can be found in muriatic acid include iron.
The color of muriatic acid is yellowish due to its impurities, while pure hydrochloric acid is clear and colorless.
Still, even though it is not as pure as hydrochloric acid, muriatic acid is a powerful acid that is very corrosive. The pH of muriatic acid is 1 to 2, which is about the same as the acidity of lemon juice or stomach acid, but it is much more concentrated and can contain up to 31% acid, making it much more dangerous than regular lemon juice.
On the other hand, while it is a potentially hazardous solution, muriatic acid is still much safer, less powerful, and readily available even for home use, unlike hydrochloric acid, which is used under very strict and diligent conditions and safety measures in laboratories and in some limited industries.
Essential Safety Measures with Muriatic Acid
Anyone who is planning on using muriatic acid should be familiarized with the safety precautions which need to be taken before, during, and after its use at home.
Here are some of the most important safety measures to follow when you will be using muriatic acid:
- You should wear appropriate protection, which includes acid-resistant gloves, full-body coverage, full face and eye protection, and a respirator when you are using muriatic acid.
- The muriatic acid must be diluted with water, with the dilution level depending on the type of job you will be using it for. In most cases, the formula for home use is 1:10 muriatic acid to water.
- When you are diluting the acid, make sure that you carefully pour it into the water to prevent it from splashing, spilling, and getting in contact with you. Never attempt to add water to the muriatic acid because this will cause the acid to propel out of the container and can get on you.
- Do not pour muriatic acid into an empty bottle or container. Make sure you have added the proper amount of water for diluting it before that.
- Use an acid-resistant plastic or glass container when preparing the diluted mix of muriatic acid with water.
- Never mix muriatic acid with another acid.
- Make sure to store the muriatic acid in the container in which you bought it.
- Keep some baking soda or garden lime nearby when using muriatic acid in case you need to neutralize it quickly. It is best to mix half a cup of baking soda with a quart of water in a spray bottle and keep it beside you every time you are using the muriatic acid.
- Always have a large container of water or a hose close to you when using muriatic acid in case you need to wash it off your skin after an accidental splash.
- If you are planning on applying the diluted muriatic acid on large surfaces and you will be using plastic spray bottles, make sure to prepare more spray bottles as the plastic will corrode and deteriorate very quickly.
- Before disposing of leftover muriatic acid, contact your local center for recycling to ensure that you dispose of the acid safely and according to the local regulations.
Effective Uses for Muriatic Acid
When used properly and with all necessary precautions, muriatic acid can be an indispensable solution for a number of home repair and maintenance projects, including:
Neutralizing the masonry alkalinity
Muriatic acid can be used for washing concrete, stone, or brick masonry, which helps neutralize its alkalinity. The alkalinity in these materials causes the burning off and discoloration of paint.
With the help of muriatic acid, you can help prolong the longevity of the paint finish with years.
The acid is diluted in a 1 to 10 ratio with water and then can be sprayed or brushed on the surface of the stone, concrete, or bricks. After letting the muriatic acid sit on the masonry for about 10 minutes, you should use a diluted ammonia solution (1 cup of ammonia with a gallon of water) to spray the wall or other surface to stop the action and to neutralize the acid.
The surface should be allowed to dry completely before any paint, or another treatment is applied.
Preparing masonry for painting by removing the efflorescence
Efflorescence on brick or concrete masonry refers to the white crystalline blooming which can appear when the masonry contains a lot of moisture.
The muriatic acid should be used to remove this blooming prior to using a sealant to help keep the moisture out of the masonry.
Muriatic acid is also a suitable solution for prepping the masonry for painting, as it will help etch the surface.
Once again, use a 1:10 muriatic acid water solution to lift the efflorescence. Brush it on or spray it on the masonry and leave it on the surface for a few minutes until the blooming starts to disappear.
Use a hard nylon brush to remove and leftover efflorescence and then neutralize the muriatic acid with a diluted ammonia and water solution with a 1:16 ratio.
Cleaning the basement walls, ceiling, and floor from mold and mildew
Muriatic acid can be used to help remove any mildew or mold from the walls, floor, and ceiling of your basement. But make sure that you are wearing all of the protective gear, especially a respiratory mask, and that you let the basement air out completely for several hours after the treatment.
To remove mold and mildew, spray or brush on a 1:9 muriatic acid to water solution on any visible spots and patches on any concrete, brick, glazed tile, or grout surfaces, and use a stiff nylon brush to scrub the patches off.
Hose down the treated surface well with water and then remove the remaining water using a wet vac.
Let the basement air out completely before you, or someone else enters it after the cleaning.
While some experts and DIYers support the use of muriatic acid for the removal of rust from stainless steel, others comment that the treatment can lead to even faster oxidation after that.
If you decide to use the acid to remove rust, remember to use it only on stainless steel surfaces and objects and never on cast iron.
Also, use the muriatic acid as a rust buster only if the surface will be painted or sealed right after the treatment.
Use a 1:10 muriatic acid water solution to brush and scrub the rust off with a stiff nylon brush. As soon as you remove the rust, immediately neutralize the acid with a paste made of an equal mixture of water and baking powder.
Apply the paste generously on the treated surface and let it sit for 10 minutes before rinsing it off with water. Let the surface dry or dry it with towels and paint it.
Maintenance of swimming pools
Muriatic acid can be used to clean the walls and floor of your swimming pool. Use a 1:16 acid and water solution to spray the surfaces of the drained pool, and let it sit for 10-15 minutes. If there are stubborn stains, use a stiff nylon brush to scrub them off.
Then rinse the entire pool thoroughly with water.
Balancing the pH of the water in swimming pools and spas
Muriatic acid can help balance the pH level of the water in the pool if it is too high. But always use muriatic acid labeled as “swimming pool acid” for this specific task. This type of muriatic acid comes with detailed instructions for the safe use of the solution for balancing the pH levels of the water in the pool, which you need to follow exactly.
A few hours after the treatment, test the pH levels of the water to ensure that it is within the desired range before you start using the pool.
How to Dispose of Leftover Muriatic Acid
Like other potent chemicals which are often used for household cleaning, repair, and maintenance, you should never drain any leftover muriatic acid down a drain in your home or property. This can harm your property and will also harm the environment.
Do not attempt to neutralize the leftover muriatic acid. Call your local center for recycling, which will help you dispose of it safely.
In the best-case scenario, they will give you the address for specialized locations for hazardous household waste where you can bring the well-sealed container of acid so that it can be disposed of properly and safely by experts.