Why do you use regular Mentos over fruit ones in a geyser?

Regular Mentos are preferred for geysers because they have a smoother surface compared to fruit-flavored ones, which can have a coating that affects the reaction. The smooth surface allows for a rapid release of carbon dioxide from the soda, creating a more explosive geyser effect. Additionally, the combination of regular Mentos and Diet Soda is known to produce the best results, maximizing the geyser height.