New shower has grout discoloration
We recently completed a bathroom renovation. After using the shower only about 3 times I noticed grout discoloration -- black like it was wet or moldy even after letting it dry out for a week. First my architect told me to clean it with a dobby sponge, which I tried but that did not work. We didn't use the shower for at least 2 weeks in a row to see if it would just dry out and return to normal color but it did not improve. Then he sent a tiler to acid wash the grout. After washing 3 times, the shower mostly looked great, except a pretty large section on the vertical rise to the shower bench and a few small spots on the floor around the perimeter. (Once again we did not use the shower during the 10 days or so that this was going on.) So about a week and a half ago they regrouted the some of the discolored grout on the vertical rise to the bench. Those same spots stayed wet looking but they told me to go ahead and use the shower (which had lost its sealer because of all of the acid washing) so that we could see what would happen. Nobody knows why these spots are staying discolored. They have told me that if this doesn't work they will bring in some company called "Grout Doctor" that basically paints an epoxy over the grout to make it look nice. My impression is that this is a service for old dirty grout when people don't want to spend the money to retile/regrout, NOT for a brand new shower. I think I have seen bathrooms where this has been done and they look terrible after awhile as it peels off. But I don't know what to ask them to do short of retiling the whole thing?? I would really appreciate any ideas both as to what might be causing this discoloration and what I should ask them to do about it. Also what is your opinion about their Grout Doctor solution?