PH meter calibration fluid question

[cvrle1]

Hey,

I was about to buy a 2 point calibration PH meter that came with the calibration fluids, so just wanted to check if these are correct ones.

It says on them: PH 4.003 25 C and PH 6.864 25 C

I read that solutions should be 4 and 7 so wasn't 100% sure about the 2nd one cause it is lower then 7.

Thanks for the help

[Pescador]

If you calibrate with 7 and 10 it's closer to the actual range you will be using.

[danny zubot]

I've wondered about that as well. I calibrated mine with 4 & 7 and my ph was all of the sudden lower than usual.