How to Lower pH in Your Pool Quickly: A Complete Guide

When your pool’s pH level is too high, it can lead to a range of problems—from skin irritation to algae growth, and even damage to pool equipment. To ensure your pool remains safe, clean, and comfortable for swimmers, it’s crucial to maintain your pH levels within the ideal range of 7.4 to 7.6. If your pool’s pH is higher than 7.8, you’ll need to take action to lower it quickly. In this guide, we’ll walk you through how to lower pH in your pool effectively using common pool chemicals like pH decreaser (sodium bisulfate) and muriatic acid.

What Is pH and Why Does It Matter for Your Pool?

The pH scale ranges from 0 to 14, with 7 being neutral. Anything below 7 is acidic, and anything above 7 is basic (or alkaline). For pools, pH is a crucial factor that determines the effectiveness of your pool's sanitizer, like chlorine, and impacts the overall health of your water. If the pH level is too high, your chlorine will be less effective, leading to cloudy water, bacteria growth, and potential damage to pool surfaces and equipment.

Your pool’s pH can be affected by various factors, including heavy rainfall, debris, high swimmer load, or even the use of saltwater systems, which tend to increase pH. Regular testing is key to preventing pH imbalances and maintaining healthy pool water.

Why Is High pH Harmful to Your Pool?

If your pool’s pH levels are too high (above 7.8), it can cause several problems:

• Reduced Chlorine Effectiveness: When the pH is too high, chlorine becomes less effective at sanitizing your pool. This means you’ll need to use more chlorine to achieve the same cleaning results, which can throw off the overall chemical balance in your pool.

• Eye and Skin Irritation: Swimmers may experience red, itchy eyes or dry, irritated skin due to high pH levels. Many people mistakenly blame chlorine for this, but high pH is often the true culprit.

• Damage to Pool Equipment and Surfaces: High pH can lead to calcium buildup on pool walls, equipment, and plumbing. Over time, this buildup can clog pipes, impair the function of pumps, and damage pool finishes.

• Fading Swimwear and Gear: Prolonged exposure to high pH water can degrade your swimsuits, goggles, and other pool gear, causing them to wear out faster.

How to Lower pH in Your Pool Using pH Decreaser (Sodium Bisulfate)

One of the easiest and most commonly used chemicals to lower pH is pH decreaser, often made with sodium bisulfate (also known as dry acid). This method is safer and less corrosive than muriatic acid, though it is usually more expensive. It’s effective at lowering pH without affecting your pool’s total alkalinity too drastically.

Steps to Lower pH Using pH Decreaser:

1. Test Your Water
   Start by testing your pool’s pH and alkalinity. Knowing your current levels will help you determine how much pH decreaser you need to add.

2. Measure the pH Decreaser
   Follow the manufacturer’s instructions to determine the proper dosage for your pool size. It’s best to start with a smaller amount and add more if needed, as it’s easier to correct if you add too little than too much.

3. Add the pH Decreaser
   Pour the pH decreaser directly into your pool, preferably near the return jets or in the deepest part of the pool. Make sure your pool pump is running to help circulate the chemical evenly throughout the water.

4. Let the Chemical Dissolve
   Allow the pH decreaser to dissolve completely. If you're using a granular product, brush away any undissolved particles to prevent damage to pool surfaces.

5. Retest and Repeat if Necessary
   After allowing the chemical to circulate for at least 24 hours, retest the water to check if the pH has dropped into the ideal range. If not, repeat the process until you reach the desired pH level.

How to Lower pH in Your Pool Using Muriatic Acid

Muriatic acid, also known as hydrochloric acid, is another highly effective way to lower pH. However, it’s important to handle muriatic acid with care, as it is a highly corrosive chemical. When using muriatic acid, always wear protective gloves, goggles, and a mask to avoid exposure to fumes or splashback.

Steps to Lower pH Using Muriatic Acid:

1. Test Your Water
   Test both the pH and total alkalinity levels to determine how much muriatic acid is needed. Muriatic acid will lower both pH and alkalinity, so it’s essential to monitor both to avoid over-adjusting.

2. Measure the Muriatic Acid
   Calculate the correct amount of muriatic acid for your pool size based on the manufacturer’s instructions. As a general guideline, for a 15,000-gallon pool with a pH level over 7.8, start by adding 1 quart (1/4 gallon) of muriatic acid. For smaller pools, start with 1 cup and add more as necessary.

3. Add Muriatic Acid to Your Pool
   You can add muriatic acid using one of two methods:

   • Method 1: Turn off the pool pump and slowly pour the acid into the deep end of your pool. This allows the acid to sink to the bottom and circulate effectively once the pump is turned back on.
   • Method 2: Alternatively, you can add the acid near the return jets while the pump is running, ensuring even distribution.

4. Dilute the Muriatic Acid (Optional)
   If you prefer, you can dilute the muriatic acid in a bucket of water (use a 10:1 ratio of water to acid) to make it safer and easier to handle. Always add acid to water, not the other way around, to avoid dangerous splashing.

5. Let the Muriatic Acid Dissolve
   Allow the pool’s filter to circulate the acid throughout the water for about an hour. After this, check the pH level. If it’s still too high, repeat the process with a smaller amount of acid.

What to Do If pH and Alkalinity Won’t Balance?

If you find that your pH and alkalinity levels are still off after adjusting, there are a few additional steps you can take:

• If both pH and alkalinity are too low, you can add soda ash (sodium carbonate) to raise both levels. Be cautious when adjusting alkalinity and pH simultaneously.
• If your alkalinity is still high but your pH is in the right range, use aeration techniques, such as a pool fountain or aerator, to help raise the pH without affecting alkalinity.

Final Thoughts

Maintaining proper pH levels is essential for the health and longevity of your pool. By using pH decreaser or muriatic acid, you can quickly lower high pH levels and ensure your pool stays clean, safe, and comfortable for swimmers. Always test your water regularly and follow the manufacturer’s guidelines to avoid overcorrecting and causing further imbalances.

If you’re ever unsure about the right chemicals to use or the correct dosage for your pool, don’t hesitate to consult an expert. Proper pool maintenance, including pH management, ensures that your swimming pool remains inviting and problem-free throughout the season.

Frequently Asked Questions About Lowering pH in Pools

• How often should I test my pool’s pH?
  Test your pool’s pH at least once a week, or more frequently if you’re dealing with frequent weather changes or heavy pool use.

• Can I swim in my pool after adding pH decreaser?
  You can swim in your pool once the pH level is balanced, typically after 24 hours of circulation. However, if you’ve used muriatic acid, wait at least 24 hours before swimming.

• Can I lower pH naturally?
  While there are natural ways to lower pH, like installing a distilled water system or aerating the water, it’s far more effective to use pool chemicals specifically designed for the task.

• How can I prevent high pH levels in the future?
  Regularly test your water and maintain balanced alkalinity levels. Consider using stabilized chlorine to avoid pH fluctuations caused by sunlight.