Tec Tile, Concrete and Grout Sealer, $10 (gal.). One of the best on the market. For tile, grout and concrete. A necessity for wet conditions in bathrooms and kitchens. 720-1000 sf/gallon.
Silicone cement/grout sealer
Water-based formula - no solvents
Improves water repellency
Leaves a natural look - does not darken most grout surfaces
Easy to apply