The color of the grout in my shower is inconsistent and in some areas the grout is a darker color?
Uneven grout color is not uncommon – although in this case, the darkening may be caused by water (more about that later). This is in part because some colors are more prone to uneven color than others due to the dyes used. Also, depending on the tile, it may be impossible to allow the grout to sufficiently cure for best color uniformity and still remove it from the tile. In other words, the grout must be removed before the color has a chance to set. However, there are many installation mistakes that can cause uneven color including improper mixing of the grout (typically by using too much water), mixing partial bags (this is a problem if the colorant was not evenly distributed), using grout from a bag that was previously opened (and gained moisture during storage), adding water after the first mixing (re-hydrating), failure to slake the grout, improper joint packing, using too much water too soon when wiping the joints, inadequate cleaning of the sponges, using unclean water, allowing
