Opportunistic feeders, their diet varies from one region to another. In the Antarctic, killer whales eat about 67% fishes, 27% marine mammals, and 6% squids. Killer whales in the Bering Sea (near Alaska) eat about 65% fishes, 20% squids, and 15% marine mammals.
Even though your shower grout looks dry, using it too early or sealing it before it's ready may damage it, leading to premature failure. Most cement-based grouts require a cure time of 48 to 72 hours before applying a penetrating sealer.
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.