how long do you wait before you seal grout
If youir using a penetrating sealer you can seal in as short as 72 hrs. No sooner. Silicone sealers you must wait 30 days for the grout to cure. Always test a small spot 1st but I ve never had a sealer change the grout darker. It will darken the grout at 1st but as it dries it will return to normal. All grout haze must be off the tile before sealing or you ll be forever scrubbing and cleaning.