RO pH

[paulhines]

Has anyone ever tested the pH of their RO/DI water? My son is doing a science experiment and is testing various samples pH. He tested my RO/DI (I was watching), and it came out at 6.2.

I would have thought it would be 7.0. What am I missing???

 

[Agu]

RO/DI water is hypothetically 7pH in a vacuum. Once it hits the air it bonds with molecules in the air and the pH drops slightly.

http://www.coleparmer.com/techinfo/techinfo.asp?htmlfile=pHPureWater.htm