I asked my tiler which he would rather do: remove the old grout and re-grout, or use the colorant. He said re-grouting would be easier for him (remember, he's doing this for free). We saw him do it, and it wasn't as difficult as I had thought. They just took it out with a utility knife. They did about 50% of the floor, since we still had stuff on it that was too hard to move at the time. I bought a $400 Fein oscillating tool for the job, and I plan to remove the rest myself. The other argument is that you could apply the colorant yourself, one section at a time, without paying for more labor. When I do stuff myself, I take forever, but I do it about a million times more carefully than any worker seems to care to do. Grout seems to be the black hole of flooring knowledge. Daltile is a very good high-line supplier, but another tile supplier was able to solve most of our problems (mainly, finding the Hydroment grout samples there). At first we had a lot of effluorescence, but they had the product that removes it effectively there as well. Good luck!

We used what Lowes/HD called tumbled marble but its surface is similar to tavertine and after grouting we used an enhancing sealer. It darkened the stone and left the grout color alone. I would recommend you try on a sample first because I was concerned also, didn't have any extra tiles and took a chance and liked the outcome. Some enhancers and grout colors could yield different results.

I think you're over thinking this. First, IMHO, anyone who puts white grout into a work space, (shower, kitchen, whatever) deserves the gray, dirty mess they fuss with for the rest of their lives. Second, a griege would be lovely, as long, I think, as it has the beige-huge with it. OTOH, you could mix dry grout powder to get something that matches very closely. Keeping in mind the shine of the tile vs. the flatness of the grout will never allow an exact match to the eye. Third, just please, please make certain you seal it. Fourth, I like your tiles.

Jan this is a floor tiles and pebble area is for under freestanding tub. The grout dust probably hasn't been completely cleaned off yet and we intend to use an enhancer to darken up the stones - just would like to make the grout look at least wet (but not sure that particular grout can be darkened since it has a stain-resister and sealer in it). Similar to this inspiration photo [https://www.houzz.com/photos/carmel-mountain-kitchen-master-and-guest-bathroom-remodel-modern-bathroom-san-diego-phvw-vp~73321082[(https://www.houzz.com/photos/carmel-mountain-kitchen-master-and-guest-bathroom-remodel-modern-bathroom-san-diego-phvw-vp~73321082)