We are having a new house built. We had a Blanco silgranit anthracite (black) undermount sink installed in a granite kitchen counter. Last week the painters washed their equipment in the black sink and now oursink has the appearance of gray with white spots. I have tried washing this discoloration out but the staining will not budge. My concern is the builder may use some harsh chemical to remove the staining and the sink will look fine for a month, then after we move in the sink will look "trashed" in a short time and we will be stuck with it then. What are others thoughts on the possibility of the builder getting this sink to look new again or do we INSIST the sink be replaced. Can an undermount sink in a granite counter be replaced with the counter in place or does the counter need to be taken off? We have our walkthu tomorrow. Thanx.