I can't seem to change from standard tuning to Open G using my Boss TU-3 tuning pedal. It works just great with normal tuning, but when I try to change to D, G, D, etc it just seems to give me false readings, particularly on the low D. I have the tuner set in the normal chromatic mode. Any ideas why I'm having trouble with this? By the way, I have the same problem with a Boss TU-2, so I doubt it's anything actually wrong with the pedal(s), but the way I'm doing it.

Thanks,
Bruce