How To Lower pH Level In Your Swimming Pool

Maintaining the correct pH balance in your swimming pool is crucial for the safety of swimmers and the longevity of your pool equipment. Here's a comprehensive guide on how to lower the pH in your swimming pool, including what you need, the relationship between pH and alkalinity, potential issues with high pH, and troubleshooting tips.

When do you need to lower pH in your swimming pool?

As we covered in our pool maintenance essentials, your pool's pH should always be around 6/9 - 7.2.

If you vary from this, your pool can start to run into problems, such as your chlorine not being as effective, swimmer discomfort, and even cloudy pool water. It's one of the core parts of maintaining your swimming pool.

What You Need

• Pool test kit: To measure pH and alkalinity.
• Muriatic acid or sodium bisulfate: Chemicals used to lower pH.
• Protective gear: Gloves, goggles, and a mask.
• Plastic bucket and stirring rod: For mixing chemicals if needed.

Relationship Between pH and Alkalinity

pH measures the acidity or basicity of your pool water, with a scale ranging from 0 to 14. The ideal pH range for a pool is 6.9- 7.2. Alkalinity, measured in parts per million (ppm), helps stabilize pH levels. The recommended alkalinity range is 80-120 ppm. High alkalinity can cause high pH, while low alkalinity can lead to rapid pH fluctuations.

Why High pH is a Problem

High pH levels (above 7.8) can cause several issues:

• Swimmer discomfort: Eye irritation, dry skin, and a sticky feeling.
• Reduced chlorine effectiveness: Making it harder to maintain clean water.
• Cloudy water: Less appealing and potentially unsafe.
• Scale formation: Calcium deposits can clog filters and pipes, leading to equipment damage.

Safety First

Before we begin, make sure to take our precautions seriously as pH decreases can cause a lot of harm if improperly handled.

When Can Muriatic Acid Create a Toxic Gas

Muriatic acid can create toxic gas, specifically chlorine gas, under certain conditions:

Mixing with Chlorine

When muriatic acid is mixed with chlorine-based products (such as chlorine tablets, liquid chlorine, or granular chlorine), a chemical reaction can occur that produces chlorine gas. Chlorine gas is highly toxic and can cause severe respiratory issues, eye irritation, and other health problems. Therefore, it is crucial to store and handle muriatic acid and chlorine products separately.

Adding to Water Incorrectly

If muriatic acid is added to water improperly, such as adding it too quickly or in large quantities at once, it can produce fumes. These fumes can be irritating to the respiratory system, eyes, and skin. Always add muriatic acid slowly and carefully, following the recommended procedures.

Poor Ventilation

Using muriatic acid in an area with poor ventilation can lead to the accumulation of toxic fumes. This is particularly a concern when working indoors or in enclosed spaces. Always ensure that you are using muriatic acid in a well-ventilated area to allow any fumes to dissipate quickly.

High Concentration

Using a highly concentrated form of muriatic acid can also increase the risk of producing toxic fumes. Dilute muriatic acid as recommended before adding it to your pool, and handle it with care to avoid exposure to concentrated fumes.

Safety Precautions

To minimize the risk of toxic gas production:

• Always store muriatic acid and chlorine products separately.
• Add muriatic acid to the pool water slowly and in small amounts.
• Use the acid in a well-ventilated area.
• Wear protective gear, such as gloves and goggles, to protect against splashes and fumes.
• Follow the manufacturer’s instructions and safety guidelines carefully.

How to Lower pH in Your Swimming Pool

There are two ways to lower your pH in your swimming pool, Muriatic Acid or Sodium Bisulfate (Dry Acid).

Using Muriatic Acid

Before beginning, make sure to take proper saftey precautions, as muratic acid can create a toxic gas. The dangers of mixing muriatic acid and chlroine can cause harm. You'll want thick gloves, safety googles, and a mask to avoid breathing in fumes. Whule it isn't a powder, it can splash back and get onto you.

1. Test Your Water

To begin, test the water in your pool to measure the current pH and alkalinity levels. This will help determine the amount of muriatic acid needed to achieve the desired pH balance.

2. Measure the Acid

Refer to the manufacturer's instructions to measure the correct amount of muriatic acid. As a general guideline, 1 quart of muriatic acid is typically required to reduce the pH by approximately 0.2 units in a 15,000-gallon pool. Ensure accurate measurements to avoid over-treating the water.

3. Add the Acid

• Method 1: Turn off the pool pump and pour a slow, steady stream of muriatic acid directly into the deep end of the pool. Allow the acid to settle at the bottom before turning the pump back on to avoid concentrated acid circulation.
• Method 2: With the pool pump running, pour the muriatic acid near the return jets. This method allows the acid to mix more evenly with the water, promoting quicker and more uniform distribution.

4. Circulate and Retest

After adding the acid, run the pool pump for at least an hour to ensure thorough circulation. Once the water has circulated, retest the pH and alkalinity levels. If the desired levels have not been achieved, repeat the process as necessary until the water chemistry is balanced.

Always follow manufacturer’s directions, but below is a quick chart for how much muriatic acid to add to your swimming pool.

How Much Muriatic Acid to Add to Your Swimming Pool

This chart will help you get to the ideal pH of 6.9 - 7.2.

Your Starting pH Levels	1,000 Gallons (4,546 Liters)	5,000 Gallons (18,927 Liters)	10,000 Gallons (37,854 Liters)	15,000 Gallons (56,781 Liters)	20,000 Gallons (75,708 Liters)
6.8 - 7.0	0 oz 0 ml	0 oz 0 ml	0 oz 0 ml	0 oz 0 ml	0 oz 0 ml
7.0 - 7.2	0.5 oz 15 ml	2.5 oz 70 ml	5 oz 140 ml	7.5 oz 210 ml	10 oz 280 ml
7.2 - 7.4	1 oz 30 ml	5 oz 150 ml	10 oz 300 ml	15 oz 450 ml	20 oz 600 ml
7.4 - 7.6	1.5 oz 45 ml	7.5 oz 220 ml	15 oz 440 ml	22.5 oz 660 ml	30 oz 880 ml
7.6 - 7.8	2 oz 60 ml	10 oz 300 ml	20 oz 600 ml	30 oz 900 ml	40 oz 1.2 L
7.8 - 8.0	2.5 oz 75 ml	12.5 oz 375 ml	25 oz 750 ml	37.5 oz 1.1 L	50 oz 1.5 L
8.0 - 8.4	3 oz 90 ml	15 oz 450 ml	30 oz 900 ml	45 oz 1.35 L	60 oz 1.8 L
Above 8.4	3.5 oz 105 ml	17.5 oz 520 ml	35 oz 1.05 L	52.5 oz 1.55 L	70 oz 2.1 L

Using Sodium Bisulfate (Dry Acid)

Often safer to use, sodium bisulfate is less corrosive than muriatic acid but will typically cost more. Always avoid adding it on a windy day, as the risk of it blowing back onto you increases.

1. Test Your Water

Measure the pH and alkalinity of your pool water to determine the necessary adjustments. Accurate testing is crucial to ensure the proper balance of your pool’s chemistry.

2. Measure the Chemical

Calculate the required amount of sodium bisulfate based on your pool’s volume and current pH level. It’s advisable to start with ¾ of the recommended amount to avoid over-correction. Adjust as needed after retesting.

3. Add the Chemical

Sprinkle the sodium bisulfate powder directly into the return jets of your pool. Be mindful to avoid adding the chemical on windy days to prevent the powder from blowing back and causing uneven distribution or safety concerns.

4. Circulate and Retest

Allow the pool pump to run and circulate the water for approximately six hours. After sufficient circulation, retest the pH and alkalinity levels to ensure the desired balance has been achieved. Repeat the process if necessary to reach optimal water chemistry.

Troubleshooting

What If pH Is Still High?

• Repeat the Process: Sometimes, you need to add more chemicals. Add gradually to avoid overshooting.
• Check Alkalinity: High alkalinity can buffer the pH, making it harder to adjust. Reduce alkalinity first if necessary.

FAQs

Q: How often should I test my pool’s pH?
A: Test the pH at least twice a week and after heavy use or rain.

Q: Can I swim immediately after adding chemicals?
A: It's best to wait at least an hour and ensure the chemicals are well-circulated and dissolved.

Q: What if I accidentally add too much acid?
A: If the pH drops too low, use baking soda to raise it gradually. Aeration can also help increase pH without affecting alkalinity.

Lowering the pH in your pool is a manageable task with the right knowledge and tools. Regular monitoring and adjustments will keep your pool safe and enjoyable for everyone.

Want to keep your pool clean?

Check out our Pool School where we go over all the tips, tricks, and more to keeping your pool clean and healthy.