Grout dye

A while back I remodeled my bathroom, as part of the remodeling I replaced  the tile in the tube enclosure and the floor. My wife picked out the colors and told the tile man that white grout would be OK in the  enclosure but did not want white on the floor tile because it would always look dirty, so they decided on a light grey, A big mistake because the grey tile always looked dirty. I can’t tell you how many times she scrubbed the tile and grout to make it look clean, but it did not work. I checked the tile stores  and they don’t sell anything that would work to change the color, they sell products that are like a paint and wont last on a floor. I needed a dye that would penetrate the grout. As a woodworker when I need to stain anything made out of Hard Maple or any close grained wood, regular wood stains won’t work well, I have to use a wood dye. That was the answer, I bought a wood dye called Transtint from a Woodcraft store, I mixed it with Denatured Alcohol and painted all the grout lines, it soaked in and dried almost immediately, A lot of the dried dye ended up on the tiles that I wiped them clean with a damp rag.  Woodcraft has many different colors of this dye