House issues new build, two years old now. Grout has been a general issue. Shower has a penny tile floor. Grey tile with black grout. The drain is in the center and the penny tile block seams are clearly visible and the black grout shouts the poor installation. The grout was suppose to be gray, but the contractor messed that up as well. The grout is unsealed poly blend from homedepot. We told the GC we were unhappy, but he would not budge. The GC was the tile installer and took it personally. We were living in an RV through a Colorado winter and let the issue go. In the last two years, the grout in areas has turn turned into faded splotches, but looks fine when wet. On impulse I took barkeepers friend and scrubbed the floor and let it dry. It faded the entire grout, but not in an attractive way. I sort of hyperventilate when I look at it and remind myself I hated it in the beginning. Can I use a grout colorant and sealer to fix it? I should have asked first, but the quarantine is affecting my judgement. Be kind.