A Guide to Using Muriatic Acid for Pool Maintenance

Muriatic acid, also known as hydrochloric acid, is a commonly used chemical in the maintenance and cleaning of swimming pools.

It is normally used to lower the pH and total alkalinity levels in pool water to ensure that it is safe for swimming and to prevent the buildup of harmful bacteria. However muriatic acid can be a dangerous and highly reactive chemical so it is important to understand how to use it properly and safely.

In this article, we will provide clear information on what does muriatic acid do for a pool and the key considerations for its use, as well as its benefits and potential drawbacks.

Why use muriatic acid in pools

The pH level of a pool is an important factor in maintaining a healthy and balanced pool environment. The ideal pH level of a pool should be between 7.2 and 7.8.

• If the pH level is too low, the water can become corrosive and damage the pool and equipment.
• If the pH level is too high, the water can become cloudy and cause skin and eye irritation.

Muriatic acid is used to lower the pH level of the pool water to bring it within the ideal range.

The importance of maintaining the pH level in a pool

The ideal pH range for pools

The ideal pH range for a swimming pool is between 7.2 and 7.8. This range is considered neutral and provides optimal conditions for swimmers and pool equipment.

When the pH level is within this range, the water is less likely to cause skin and eye irritation, and the chlorine in the water will be more effective at killing bacteria and other harmful substances.

Problems with low and high pH levels

If the pH level in a pool is too low, the water can become corrosive and damage the pool and equipment. This can lead to expensive repairs and decreased enjoyment of the pool. Additionally, low pH levels can cause skin and eye irritation, making it uncomfortable for swimmers.

On the other hand, if the pH level is too high, the water can become cloudy, reducing visibility and making it difficult to see the bottom of the pool. High pH levels can also cause the chlorine in the water to be less effective at killing bacteria and other harmful substances.

How muriatic acid adjusts pH level

Muriatic acid works by releasing hydrogen ions into the pool water, which in turn decreases the pH level.

The pH level is a measure of the acidity or basicity of a solution and is measured on a scale of 0 to 14.

• A pH level of 7 is neutral
• A pH level less than 7 is acidic
• A pH level greater than 7 is basic.

By adding muriatic acid to the pool water, the hydrogen ions lower the pH level, bringing the water closer to the ideal range of 7.2 to 7.8.

How much muriatic acid to lower pH in pool

How much muriatic acid to add to pool water to adjust the pH level depends on the size of the pool, the current pH level, and the desired pH level.

It is important to measure the pH level of the pool regularly using a test kit or test strips and to add the appropriate amount of muriatic acid to the pool.

Too much muriatic acid in pool water can cause the pH level to become too low, which can be dangerous for swimmers and can damage the pool and its equipment.

This table shows how much muriatic acid to lower ph in pool that holds 10,000 gallons to reduce the pH down to 7.5:

pH Level	Muriatic Acid (ounces)
8	5 – 8 ounces
9	10 – 16 ounces
10	16 – 24 ounces
11	24 – 32 ounces
12	32 – 40 ounces
13	40 – 48 ounces
14	48 – 56 ounces

For larger (or smaller pools) use the same proportion so to lower the pH from 10 in a 25,000 gallon pool add between 40 and 60 ounces (multiply by 2.5).

Although I have used muriatic acid at times, I rarely need to use it. This is largely because I do not normally use liquid chlorine to shock my pool. Liquid chlorine has a pH of 13 so using it is likely to increase the pH and require muriatic acid to lower it again.

How to use muriatic acid in pool

It is important to always add muriatic acid slowly and to test the water at intervals to ensure that the desired pH level is reached and maintained. Adding too much muriatic acid can lead to a dangerous drop in pH, so it is always best to add it in small increments and to monitor the water’s pH level regularly.

You should also avoid adding the acid directly to the pool, as it can cause skin and eye irritation. Instead, add the acid to a bucket of water and stir it in. Then slowly pour it into the pool walking around the edge as you do to distribute it evenly.

Run your pool pump to ensure the acid is mixed throughout the pool.

Safety when adding muriatic acid to pool

Proper handling and storage of muriatic acid

Muriatic acid is a highly corrosive and strong mineral acid, and it is important to handle and store it properly to avoid injury. It is important to store it in a cool, dry place away from flammable materials and to keep it out of reach of children and pets.

Never mix acid with any other chemicals.

Protective gear to wear when adding muriatic acid to the pool

When adding muriatic acid to a pool, you should wear protective gear to avoid skin and eye irritation. This can include gloves, eye protection, and a long-sleeved shirt. It is also important to avoid inhaling the fumes from the muriatic acid, as they can be harmful.

Precautions to take to avoid skin and eye irritation

If muriatic acid comes into contact with the skin thoroughly wash the skin in clean water. If muriatic acid gets in the eyes, it is important to rinse them immediately with water for at least 15 minutes and to seek medical attention if necessary.

Using muriatic acid with a vinyl liner

If you have a vinyl-lined pool you should use muriatic acid sparingly as there is a possibility it may affect the liner, particularly if you have a patterned liner.

You would be better advised to use dry acid instead of muriatic acid to lower the pH if you need to.

Using dry acid vs muriatic acid

Dry acid is actually sodium bisulfate which, as the name suggests, contains sulfates. Over time sulfates can build up and start to attack the structure of your pool.

Muriatic acid on the other hand is chlorine-based and is actually also produced by the body in the form of stomach acid. This will not adversely affect the pool’s structure. It is also normally cheaper than dry acid.

Muriatic acid FAQs

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