A question I have is why are your electrodes going black? Do you not have reverse polarity working? Are you only using the one silver electrode rather than two? Is that because of the larger silver electrode and the expensive of using two such electrodes? The black must be Silver Oxide forming on the electrode but why is it doing that unless reverse polarity is not used.
Is there an option to disable reverse polarity or does the SilverTron Elite not support it?
That might mean that you cannot use reverse polarity for some reason because reverse polarity should prevent the electrodes going black.