re-coloring tile grout
We use grout stain all the time at my work to either fix a mix up in grout colour, or when we have to go back 10 years later and do a tile replacement and the grout around it now doesn't match the rest, we sometimes have to stain the whole floor. Both TEC and Aquamix make one and they're great. They're an epoxy formula and are guaranteed for 10 years. You could literally turn black grout white if you wanted and it still looks like grout, not like paint on grout. Depending on your colour depth change you may need to do two coats, and one bottle does about 200 s/f one coat, IF you have to get more than one bottle, MAKE SURE the batch number is the same or you could be back in the same situation with grout being different colours. Tip: Our guys prefer to cut off the outer edges of a toothbrush and use that to put it on rather than a paint brush, just cut to slightly smaller than your grout joints.