Friday, 5 February 2021

Why is pH Important in Your Swimming Pool?

Swimming pool pH is often a test factor that is misunderstood or not given the proper attention. We know it is one of the big 3 test factors alongside Chlorine and Alkalinity but why I the pH important to measure and keep in the range each week? I go over pH in-depth with chemistry expert Bob Lowry.




Bob Lowry has created over 100 chemicals used in today’s Pool & Spa Industry and has written over 20 books on pool & spa chemistry.  He has been in the industry for over 47 years and is the Lead Consultant at Lowry Consulting Group, leads the Pool Chemistry Training Institute, and has created the Certified Residential Pool & Spa Certification Program. Learn more at  https://pcti.online/

Here are some other recordings I did with Bob Lowry:

pH and Why it is So Important in Balancing a Pool With Chemistry Expert Bob Lowry (this video):

Raising and Lowering the pH in a Pool With Chemistry Expert Bob Lowry: https://www.buzzsprout.com/110832/7361284

The Different Chorine Types With Chemistry Expert Bob Lowry: https://www.buzzsprout.com/110832/7361323

Non-Chlorine Shock and Shocking a Pool with Chemistry Expert Bob Lowry:

Saltwater Generators Pros and Cons with Chemistry Expert Bob Lowry:

pH is the most important test factor for your swimming pool and if it gets out of balance there are many negative effects that you will encounter. The ideal pH is 7.5. Most experts agree that 7.4-7.6 is the range the pH should be maintained at in your swimming pool.

Low pH will cause: 
Corrosive Water 
Stains
Etched plaster
Eye & Skin Irritation
Cloudy Water
Increased Chlorine Activity
Destruction of Total alkalinity
Stretching of Vinyl Liners
Blistering of Fiberglass Pools

High pH will cause:
Scale Formation
Stains
Cloudy Water
Short Filter Cleaning Cycles
Eye & skin Irritation
Poor Effective Chlorine 

Testing for pH:
Testing once a week is ideal. For a new pool start-up testing daily for the first two weeks is recommended. But once a week will give you a good indication of how stable the pH is in the pool water. There are various ways of testing the pH; test Strips, basic test kits, and Taylor Kits that use reagents. Alternate testing can be done with the ColorQ Pro7 Photometer testing and Digital pH testers.  

Lowering high pH: 
If the pH starts to get high in your pool the only way to lower it by adding acid. Either a dry acid or liquid acid. Muriatic Acid of 31.45% is the most common acid used to lower the pool's high pH. Dry acid or Sodium Bisulfate is the dry form of acid that can be added to lower the pH. Some test kits like the Taylor K-2006 will have an Acid Demand Test. This is a reagent test that will tell you how much acid to add to your pool to lower the pH. A chart is included with pool gallons and how many pint or quarts to add depending on the test results. 

Raising low pH:
If your pH is low you can raise it up using a base. A base is the opposite of acid and it will raise the low pH up in your pool rapidly. The best base is Borax as it will raise the pH without raising the Total Alkalinity.  Baking Soda (Sodium Bicarbonate) works well also but it is mainly used for raising the Alkalinity and requires large amounts to raise the pH. Soda Ash (Sodium Carbonate) raises the pH well but it also raises the pool's Alkalinity up so use Soda Ash if Borax is not available in your area.


Bob Lowry has written extensive Tech Bulletins and here is an excerpt from one on pH for you.

Source:
https://ift.tt/2MvfluZ

“You would think that adding muriatic acid, dry acid, soda ash, or even bicarb for adjusting pH and alkalinity would be a simple calculation. This is reinforced by the fact that there are charts and tables listing the amount of acid, soda ash or bicarb needed to lower or raise pH and alkalinity. This leads you to believe that the amount of acid needed to change pH from 8.0 to 7.5 will be the same regardless of the alkalinity, CYA, borate, calcium hardness, salt, and water temperature. Not true. All of these water conditions have an effect on the amount of acid, soda ash, or bicarb needed to make the changes.

Hydrogen Ions Are the Key
With the help of Richard Falk, we have created a very accurate spreadsheet that takes into consideration all the sources of hydrogen ion (H+) change in pool and spa water. There are equilibrium shifts for CYA, borate, carbonate, ionic strength, calcium hardness, and temperature plus the starting pH and alkalinity. I hope to create an App that you can use on your cell phone but it may take some time for programming and user interface (how the information is displayed on the cell phone screen to be useful).”

The article goes into very detailed explanations of pH and it is worth reading the entire write up by Bob Lowry.





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