Electrolysis occurs when your coolant becomes acidic. Now you have a big battery with metal removed from one surface (typically your aluminum components) and deposited on another. Zincs are designed to be sacrificial, which assumes that electrolysis is present. If you don't want to eliminate the threat, I guess a
zinc anode is a solution, but the correct solution is to eliminate the electrolysis. You do this through a good
antifreeze with regular maintenance of your cooling system.