Here's the calibration instructions:
Unwrap meter from packaging.
Sort plastic from paper inserts.
Recycle according to your town's recycling program. The meter can just go in the trash.

Sorry... I couldn't resist. Hanna makes crappy products.

Okay. The reason there are 2 values, 6.86 and 7.01, is that the NIST buffer 'neutral' is actually 6.86. (.025 molar disodium phosphate at 25'C is pH 6.86). You have to hit the 'mode' button during the calibration to tell the meter you are using the NIST buffer set (4.01-6.86-9.18) instead of the more common 4.01-7.01-10.01 buffers.

So read the packaging on your calibration standards to see which calibration mode you will need to run.
stinkyattic Reviewed by stinkyattic on . Anyone have instructions for Hannah Ph meter? So i took my newly purchased, used digital ph/ppm meter up to the local hydro shop so i could get it calibrated. Well the guy didn't know shit about hannah meters and after messing with it for a bit, he gave up. I did buy 7.0, 4.0 and ppm calibration solution. My question is: Why does it say while calibrating ph, "use 6.86"? it use to say use 7.01. then it goes to use 4.01. So I do all of that, using 7.0 where it says 6.86. Still reads funny. maybe i need a new electrode? Any info on the Rating: 5