Ph Probe Calibration Help

[Madreefer]

When calibrating probes do you use the 3 different solutions or just 1? It seems that if I use the 4 and than try to calibrate with the 7 or 10 I get inconsistant readings. I have a monitor that I use for the tank and a seperate controllor that I use for my reactor. When I swap the probes I get different readings. They are both Pinpont and using Milwakee solutions. What am I doing wrong?