HELP! We recently had polished white carrara penny marble mosaics installed in our shower floor. It's beautiful; however, I noticed after it was grouted that there is an obvious line where apparently the marble was from two different dye lots. I realize I should have checked this prior to installation, but I was wondering if there was a way to fix this now by lightening some of the darker marble to help it "blend." Maybe bleach or hydrogen peroxide? After speaking with our tiler, our only other option is to lay another tile over it. We used an epoxy grout, and removing it would apparently ruin all the underlayments that he just installed. I really DO NOT want to do this. Any advice or experience is greatly appreciated!!