Recommendation to darken grout. This Prism Natural Gray came out a shade or two lighter than the swatch and is not the look I wanted. I want/need a more muted grout line.
How to Change Tile Grout Color | Cosmos Surfaces
How can I get my grout darker?
How to Seal Grout - Black Diamond Coatings
Custom Building Products TileLab 0.2 qt. Penetrating Sealer for Tile & Grout TLGS6Z - The Home Depot