Different reading in pH meter

I have 2 pH meter and both give 2 different readings ,a difference about 0.3. I check the electrode and its performance is OK. Can you tell me what can I check else.


calibrate both ph meters with buffer solutions and then perform pH again.

I calibrate the ph meters with the same buffer solutions , the readings were 1.30 for Hanna and 1.66 for Consort

Try by exchanging the electrodes and see the difference to locate where the actual trouble is whether it is with the electrodes or with the basic electronic unit.

Are both equipment the same?
Are the electrodes for the same function?

If I am correct pH value may be change due to change in temperature, you have to verify that ATC is on in either pH meter and check MV value for both pH meter.