The Best Ways to Lower Your Pool’s pH

Any pool owner knows maintaining optimal pool chemistry in a swimming pool is one of the most important parts of achieving sparkling clean pool water. pH level can be one of the trickiest to maintain, as it can easily be thrown out of balance by anything that ends up in your pool water. Here we will discuss the reasons why it is important to keep your pool pH level in the optimal range, as well as the best ways to lower your pool’s pH when it becomes too high.

What is pH?

Simply put, pH is the measure of how acid or basic (alkaline) a substance is. pH is measured on a scale from 0 to 14. Substances with a lower pH are more acidic, while those with a higher pH are more alkaline or basic. A pH level of 7 is neutral. The ideal pH for a swimming pool is 7.2 – 7.8.

Why is Pool pH Important?

When the pH in your pool is outside of the optimal range, it can cause a host of problems and cost you a lot of time and money. Proper water pH lessens the chance of eye and skin irritation in swimmers, allows chlorine to do its job of keeping the pool clean and clear, and protects pool surfaces from corrosion, buildup, and staining.  Ideal pH levels are also important in protecting your equipment - especially pool heaters!

What Causes High pH in Pools?

When you find that your pool’s pH is too high, it could be caused by any number of factors including:

  • Pool shock. It is important to shock your pool as part of your pool maintenance routine, but chlorine-based pool shock raises your pool’s pH. Be sure to regularly check your pool chemistry, especially after shocking the water.
  • New pool plaster or pebble surfaces. This can cause high pH for about a year after installation.
  • High alkalinity. When total alkalinity is too high, this raises the pH level as well. The pH and alkalinity level are closely related, so when one is off, the other usually is as well.

What Happens When Pool pH is High?

A high pH level can lead to many different problems in your pool, including:

  • Cloudy water
  • Scaling on pool surfaces and at the waterline from calcium deposits
  • Reduced chlorine effectiveness, so you have to use more to keep your pool clean
  • Algae blooms
  • Clogged pipes and pool filters
  • Skin and eye irritation in swimmers

Chemicals to Lower Pool pH

It is important to regularly test your pool water using a high quality test kit or test strips to make sure the pH is balanced. When you find that your pool has a high pH level, there are two different pool chemicals which are commonly used to bring the pH down: muriatic acid and sodium bisulfate (pH-).  Muriatic acid, also called hydrochloric acid, is a strong, liquid chemical that also has many commercial uses. Sodium bisulfate, also called dry acid or pH-, is a fine powder that some people prefer to work with because it is not as harsh as muriatic acid. It is important to note that liquid acids like muriatic acid can burn your skin and cause damage to pool decks and surfaces, so use caution, wear protective clothing, and always follow the manufacturer’s safety instructions.

Steps to Lowering Pool’s pH

  1. Test the pH and alkalinity. pH should be between 7.2 – 7.8 and alkalinity should be between 80 – 120 ppm.
  2. To lower the pH, measure dry acid such as Doheny’s pH Minus according to the manufacturer’s instructions.
  3. Dohenys’ highly suggests that when adding any chemicals to your pool water, they should be diluted with water first.  Remember to always add chemicals to water and NOT water to chemicals!
  4. Add the chemical slurry (water + pH-) to your pool water, preferably in front of one of your water return jets.  NEVER add any shocks or adjustment chemicals or chemical slurries to your pool skimmer(s).  If you are using muriatic acid, pour the acid into a large plastic bucket full of pool water and carefully dump the mixture into the deep end of the pool with the pump turned off.
  5. Let the chemicals circulate throughout the water for at least 4 hours
  6. Retest the pool water and repeat the process as necessary until your pH has reached the optimal range.

With proper testing and the right pool chemicals, it’s easy to keep your pool water pH balanced so you can protect your family, your pool equipment, and your wallet. If you have questions about any of our pool products and how to use them, contact our friendly experts today at 800-574-7665 or visit us online at