I have a porcelain tile floor in my foyer and kitchen that was put in 5 years ago. The tiles are fine and level. From the start, though, the grout was not right, but not awful enough for me to insist it be redone. I was in the middle of a big kitchen renovation and had bigger fish to fry,

Fast forward, and last week I had the entire floor re-grouted. Now I'd like to keep it that way. I think I should have it sealed, and would like some recommendations for an excellent sealer.

The grout lines are narrow, about 1/8 inch, and the grout used was tec AccuColor Premium Unsanded Grout. It's a medium gray which is very close to the color of the tiles, so I wouldn't want anything that will change the color.

Suggestions?