Measuring pH in soft water

[Ttw]

It is sometimes difficult to get a good reading of pH with a meter such as the Hanna in soft water. I have heard that the situation can be improved by adding a little NaCl to the water. When I do this , the pH changes. Is this a legitimate way to more accurately measure the pH?

 

[Josh]

Paging our resident water chemistry experts. From what I remember in college, adding a bit of NaCl should not effect the pH. I'm not sure if it will help in getting a more accurate pH reading...

 

[regani]

If you are adding salt, make sure it is pure NaCl. The commercial table salts contain anti-caking agents. As the salt is relatively unrefined it may also contain carbonate or bicarbonate which will affect the pH. Adding pure NaCl will not change the pH.
Alternatively you can try to get some potassium chloride (KCl) which generally does not contain problematic impurities.

And yes, it will get a more accurate pH reading

 

[Josh]

I learned something new today! Thanks @regani