You were saying in earlier posts that polarity reversal was unnecessary! Polarity reversal does not stop plating of the electrode, it does reduce it because there are two electrodes.
What you seem to have missed is that the maker of your generator recommends using an electrolyte to prevent the blackening of the electrode. He recommends Sodium Carbonate. Not Sodium Chloride which I think you might of mixed up with all the negative press that sodium chloride ie salt and Colloidal Silver has. These are very different things and have different effects. An electrolyte both speeds up production by increasing conductivity of the water and stops/significantly reduces the plating of the electrode.
If you read up on it on your manufacturers forum he explains the chemistry and how it works.