Ph of RODI vs Distilled

[LadyTang2]

I read this: "Pure distilled water should be neutral with a pH of 7, but because it absorbs carbon dioxide from the atmosphere, it's actually slightly acidic with a pH of 5.8."

Does this also mean that 0 TDS RODI water also has a low ph around 6? Why or why not?

 

[JimWelsh]

Yes, very quickly after it comes out of the unit and is exposed to atmospheric CO2, and for the same reason as distilled water. Note that it is very difficult to meaningfully measure the pH of either distilled or RODI water, since it has virtually zero buffering capacity.