I recently had a room tiled using a dark brown grout that is now much
lighter than when first applied. I thought this was due to the grout dust
but no amount of scrubbing and vacuuming has helped. I'd like to apply a
sealer but I'm afraid to until the color is fixed. In fact I tested a
small area with sealer. The wet sealer turned the grout the correct color
until it dried. Any thoughts as to why it looks too light and how to fix
the situation?

Thanks,
crabshell