High pH Low Alkalinity

Through the years I have run across different scenarios of pH and alkalinity some of which are kind of hard to understand or make no sense but as a pool owner-operator, you need to balance the chemistry starting with alkalinity regardless of pH before they have a negative effect on the pool water. How do you fix High pH with Low Alkalinity?

Put pool filter on recirculate
Run pump
Add soda Ash or sodium bicarbonate to raise alkalinity
Evenly distribute powder on the pool’s surface by walking around the pool
Waiting at least 6-8 hours for retesting TA
Once the alkalinity reading is 80-120 ppm
Lower pH to 7.2-7.6 with a pH-down product


The most important reason for balancing the chemistry of your pool or spa is to allow the chlorine to do its job as efficiently as possible because if the pool’s water is not balanced then this renders chlorine ineffective which will allow bacteria to grow and take over. This is why pH and Alkalinity are so crucial to the water chemistry of pool water.


Effects of High pH on Pool Water


If the pH gets higher than 7.8, the water is becoming too alkaline. When water is too alkaline, it reduces the effectiveness of chlorine disinfection the pool chemical that kills pathogens. Pool water with a pH level that’s too high also can cause skin rashes on swimmers, cloudy water, and scaling on pool equipment in a pool and spa.

Over time, scaling inside pipes can build up, restricting water flow and putting a strain on your pool circulation system that can lead to costly repairs for pool, spa, and hot tubs. Steps should be taken to lower the pH.

A pH reducer added to the pool water will lower the high ph of the water. Chemicals like muriatic acid will lower the pH level of your pool water. Doses of muriatic acid should be taken in steps to the pool water and tested every few hours.

High pH is just as ineffective as low pH in your pool. If your swimming pool is experiencing high pH conditions and gets excessively high, the water becomes overly soft. Swimmers can develop skin irritation alongside dryness and red eyes. Too high a pH level can also destroy piping and pool water filter equipment.

The use of some chemicals like Shock chlorine, or Algaecides and even the natural effect of aeration can raise the pH in your pool water by gassing off Co2 and replacing the Co2 with Carbonic Acid which is then replaced with Bicarbonate Ion.  This causes the ph in the swimming pool to fluctuate naturally.

If the pH level is above 7.8 then you can expect the water to become cloudy and to see scaling along the pool sides. Metal parts of your pool can also corrode, and vinyl linings may wrinkle if the water is too acidic

When water is too high a pH, it reduces the effectiveness of chlorine the pool chemical that kills bacteria and pathogens. Water with a high pH that’s too high also can cause skin rashes, cloudy water, and scaling on pool equipment. Over time, scaling inside pipes can build up, restricting water flow and putting a strain on your pool circulation system that can lead to costly repairs.

High pH in pools:

  • Chlorine is around 50% less effective at pH levels over 8.2 in pool water
  • Scaling from calcium deposits on pool surfaces and waterline
  • Algae bloom likely
  • Pool water may appear cloudy and dull

Effects of Low Alkalinity in Pool Water


Total Alkalinity(TA)  in swimming pool water is an important step in keeping stability and chemical working especially chlorine. Water contains ionic compounds that are Alkaline in nature. They act as a buffer for keeping the pH in your pool from slippingThink of it as a muscle for pH. If lower Alkalinity is not balanced things go haywire fast! The pH of the pool level can get crazy.

Adjusting the alkalinity of pool water is an important first step for establishing a good chemical balance in your pool. Keep in mind that the lower the alkalinity, the more difficult it is to manage pH and disinfection rates in your pool. If your pool starts to test for a high pH, a quick response can save you some hassles.

High or low Total Alkalinity level is very closely related to pH, as it is a measurement of all alkaline substances in the pool water. Proper Alkalinity levels are a key factor in maintaining pH  many describe it as being a “pH buffer.” Low Total Alkalinity levels cause rapid pH fluctuations, and high levels make pH difficult to adjust.

That said, it’s best to adjust one and then the other, not both at the same time. If Total Alkalinity is out of balance, address it first. The total Alkalinity level is brought back up to the proper recommended standard for swimming pools and spas which measured between 80-110 ppm Total Alkalinity (TA).

For a saltwater chlorine generator, most manufacturers recommend TA levels between 80-120 ppm. Maintaining the right balance of pH and Total Alkalinity is essential to keeping your pool water and spa water in good condition. If you can buy a good reliable test kit and don’t use test strips.

So make sure you understand the basics of each test you’ll be running and that your kit and reagents are fresh (they should have an expiration date stamped on each bottle) before Testing Pool Water.

The stronger the muscle or Total Alkalinity in water the less chance that pH moves up or down leaving that ideal range in the pH scale that is needed for the optimum level to keep your pool water sanitized and for chlorine to work properly. This pH and Alkalinity testing are critical for controlling your pool no matter the size or amount of water it holds.

Low Alkalinity in pools:

  • Etching of pool plaster
  • Vinyl liners become stiff and brittle
  • Corrosion of metals in ladders, handrails, and heat exchangers
  • Swimmer comfort issues, including burning eyes and dry skin
  • Pool and Spa surface stains
  • Rapid fluctuations in pH, known as “pH bounce”


How to Adjust High pH With Low Alkalinity in Pool Water


Everything in water chemistry starts with alkalinity no matter what’s happening in your swimming pool whether it’s a concrete inground pool or a vinal above-ground swimming pool Total Alkalinity (TA) level has to be adjusted in the good operating range of 80-120ppm.

To bring down the pH level, use a chemical additive called pH reducer or pH minus. The main active ingredients in pH reducers are either adding muriatic acid or sodium bisulfate (also called dry acid). Reducers are readily available at pool supply stores, home improvement centers, and online.

Before you do-Remember you must bring down Alkalinity (TA) before you adjust the pH in the swimming pool water. If the pH of the pool is too low then use a ph increaser (sodium carbonate) to bring both pH levels up after the alkalinity is balanced in the pool.

Always start here with Alkalinity which is the basis of pool chemistry:

  1. Bring low Alkalinity up first in the pool
  2. Put pool filter on recirculate
  3. Add soda Ash, and sodium bicarbonate, better known as your household baking soda which is an effective product used to raise the alkalinity in your pool
  4. Evenly distribute by walking around the perimeter of the pool broadcasting the powder across the entire pool using gloves and goggles for protection
  5. Waiting for at least 6-8 hours for retesting the pool
  6. Once the total Alkalinity (TA) reading is 80-120 ppm in the pool
  7. Lower high pH level in pool targeting  7.4 with a pH-down product


The correct amount of a pH reducer depends on the water volume of your pool and its current pH level. High pH reducers usually come with a guide that takes into account the variables and calculates the proper amounts of pH reducer in steps to add to your pool water.

Low pH High Alkalinity

For more great informative articles on pH, Alkalinity, and mastering your swimming pool like this one stay here at MyWaterEarth&Sky- when, you own a swimming pool, especially a busy bigger inground pool you’ll run into balancing problems that have to do with alkalinity, pH, and chlorine residuals that over time……………Continue reading



JimGalloway Author/Editor



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