[bsherwood]

my ph meter came in the mail. I have to calibrate in 250 ml of di water with the added buffer that they sent.

DI water? where do I get some. It isn't distilled and the interweb says it's not RO water....(however I have to think RO water would work)

I teach at a HS is my science dept going to have some DI water on hand?

thanks in advance.

 

[Calestus]

Distilled water, available at any grocery store and almost all pharmacies will work for calibration.

 

[bsherwood]

groovy! thank you....

i'm slow, but I'm stupid

 

[Zhylis]

DI water - de-ionized: contains no cations or anions (ie Mg2+, Ca2+, Fe3+, Cl-, etc.), can contain uncharged contaminants, won't SNAFU a pH meter calibration

distilled water - re-condensed water vapor: contains very little ions, can contain contaminants with a similar boiling point as H2O

RO water - diffusion through a size-exclusion, semi-permeable membrane: contains slightly more ions and other contaminants in comparison to the other two methods

Honestly, any of these three can be used to calibrate a pH meter; there's no need to be accurate out to the third decimal place with an aquarium.