How To Balance pH Levels in a Pool

When it comes to the actual enjoyment of our pool or hot tub/spa, one water balance element is more important than all others: pH.

A pH level that is too high or too low causes skin and eye irritation, affects equipment and pool/hot tub/spa surfaces, and has an impact on the effectiveness of sanitizers.

So what is pH?

pH measures how acidic or basic a solution is. The pH scale goes from 0 to 14 with 7.0 being neutral. Anything below 7.0 is considered acidic and everything above 7.0 is considered basic.

Here's how that relates to pools and hot tubs/spas:

Scale Ideal Acceptable
pH 0 - 14 7.4 - 7.6 7.2 - 7.8

Everything has a pH. Coffee has a pH of 5.0. Most hand soaps have a pH of 9.0-10. The fluid in your eye has a pH of 7.4. Lemon juice, on the other hand, has a pH of 2.4. If you've ever squirted lemon juice in your eye you know it burns. It burns because the pH of lemon juice is well below 7.0, which makes it very acidic. So the reason why your eyes sometimes burn during or after you swim in your pool is because the pH level in your pool is below the acceptable range.

The lower on the scale your pool pH levels are, the more acidic and corrosive your water becomes. The higher on the scale your pool pH levels are, the more basic and alkaline your water becomes, leading to scale formation.

So the goal is to keep the pH as close to the ideal range as possible to help ensure proper water balance.

The basics include:

Always take proper precautions and wear proper Personal Protective Equipment when balancing pH.

Add soda ash if your pool's pH level is below 7.2. Add Muriatic Acid or Sodium Bisulfate if it's above 7.8.

Continue to add appropriate product until your water has a pH level of 7.2-7.8 (ideally 7.4-7.6).

Balance the pH in pools

Necessary Job Materials: 

  • Safety Glasses or Goggles
  • Gloves
  • Leslie’s Soda Ash
  • Muriatic Acid
  • Leslie’s Dry Acid
  • Complete Test Kit/Strips

Steps for balancing pH in pools

If after testing your water, you find that the pH is below 7.2 on the pH scale, add a soda ash (such as Leslie's Soda Ash) at a rate of 1 pound per 10,000 gallons every 4 hours, re-testing before adding additional product.

DIY TIP: If you are attempting to adjust pH, you will also be adjusting Total Alkalinity at the same time. Always retest both after adding pH or Total Alkalinity adjustment chemicals.

To dilute the Soda Ash, add the ash to a clean bucket of pool water. Use a plastic or wooden utensil to mix before pouring the mixture around the perimeter of the pool with the circulation system running.

Add chemicals to water. Never add water to chemicals.

If after testing your water, the pH is above 7.8 on the pH scale, add Muriatic Acid or Sodium Bisulfate (such as Leslie's Dry Acid) at a rate of 16 fluid ounces per 10,000 gallons every 4 hours, re-testing before adding additional product. Muriatic Acid or Sodium Bisulfate is added to the pool after being diluted with water.

DIY TIP: When working with liquid or dry acid, take special precautions to maintain a safe working environment. Always follow proper mixing procedures.

To dilute the Muriatic Acid or Sodium Bisulfate, fill a clean bucket with 3-4 gallons of pool water, then add the recommended dose of Muriatic Acid or Sodium Bisulfate per the pool’s volume to the bucket of water. Mix the water and acid solution with a plastic or wooden utensil. Pour the acid solution evenly around the perimeter of the pool and away from fixtures and skimmer, with the circulation system running.

DIY TIP: Leslie’s Dry Acid should be used in place of other Muriatic Acid options in vinyl liner, fiberglass, painted and tile pools. Follow the label directions for dosing information.


Balance the pH in hot tubs/spas

Necessary Job Materials: 

  • Safety Glasses or Goggles
  • Gloves
  • Leslie’s Spa Liquid pH Up
  • Leslie’s Dry Acid
  • Complete Test Kit/Strips

Steps for balancing pH in hot tubs/spas

For an above-ground hot tub/spa, soda ash is not to be used. So if you have low pH in your spa or hot tub, use Potassium Carbonate (such as Leslie’s Spa pH Up). Add Leslie’s Spa pH Up at a rate of 1 fluid ounce every 30 minutes, testing in between doses to ensure proper pH balance.

For an above-ground hot tub/spa, muriatic acid is also not used. So if you have high pH in your spa or hot tub, use Sodium Bisulfate (such as Leslie’s Dry Acid). Add Leslie’s Dry Acid at a rate of 1 ounce per 500 gallons every 30 minutes, re-testing before adding additional product. Leslie’s Dry Acid is added to the spa after being diluted with water.

To
dilute Leslie’s Dry Acid,
fill a clean bucket with 1 gallon of spa water. Next, add the recommended dose
of Leslie’s Dry Acid per the spa/hot tub’s
volume to the bucket of water. Mix with a plastic or wooden utensil to aid in dissolving. 
Pour the acid mixture
into the spa or hot tub with the circulation system running.


Hopefully you now have a better understanding of pH and how to manage it in your pool or hot tub/spa. If you ever need help, call or visit your local Leslie's store or call 1-800-LESLIES.