The Anode supplies metal ions to the solution for plating. The Anode slowly wears away during plating and eventually needs to be replaced. Clean the Anode Bar after every few minutes of plating to remove the dark buildup. (Use an old toothbrush & distilled water). DO NOT CLEAN BAR WHILE IN THE PLATING SOLUTION. Use Replacement Electrolyte Solution (10049 ZB) to replace contaminated solution or for plating larger parts.