I have a small opening in my shower tile floor that is grouted with epoxy grout. It is collecting water. I've dried all the water that has made it in the opening but want to know if I need to use epoxy grout to fill in small opening or if I can just use regular grout.
It is usually always better to use like materials when fixing something. If you use regular concrete based grout to patch a hole in epoxy grout, not only can you not be sure of a texture and color match, there is the risk that different expansion rates will simply cause the concrete to crack.
Not to mention, concrete grout is not stain proof, nor water proof. Epoxy grout is both. So eventually the difference will show...