It's probably due to a polarity reversal that can occur when a charge is reduced, lost or reversed because it's directly in the path or field of an opposite charge with greater potential. Platers call these stray currents. Very common in unlined tanks or tanks where sidewall conductivity grows over the years. *************************************************************************** * TechNet mail list is provided as a service by IPC using SmartList v3.05 * *************************************************************************** * To subscribe/unsubscribe send a message <to: [log in to unmask]> * * with <subject: subscribe/unsubscribe> and no text in the body. * *************************************************************************** * If you are having a problem with the IPC TechNet forum please contact * * Dmitriy Sklyar at 847-509-9700 ext. 311 or email at [log in to unmask] * ***************************************************************************