Differing from cell voltage and line current, anode current signals can provide an insight into the localized anodic dynamic behavior in an operating Hall-Heroult reduction cell, and can be used as an alternative in-depth method to study the process in the hostile industrial potline environment. This work involves further investigations on changes in the frequency response of anode current signals (such as peaks and magnitudes) with anode age and anodic reactions. Furthermore, two process abnormalities, anode effect and anode slippage, are studied. This study demonstrates that anode current signals provide an earlier indication of an approaching anode effect than the conventional cell voltage measurements. Frequency domain analysis has been found to be an additional identifier, in separating anode effects from other abnormalities, that can also cause anode current redistribution.