Sealing tile grout is a great way to increase the maintenance and the long term durability of your tile floor. It also will prevent discoloration.
Adding grout sealer may very well darken, but not change the color of your grout. As you apply the seal, you may notice your grout change 1 or 2 shades.
Testing Before Applying
Take necessary steps to test your grout sealer before you apply it to your entire floor. Although most grout sealer will not change the color of your grout, you should always test it in a hidden spot to ensure that it looks like you would expect it to look when dry.
Topical Sealer vs Penetrating Sealer
Grout sealer typically comes in 2 forms. The first is called a topical sealer. This type seals the actual surface of the grout without going any deeper. Once you have sealed the grout, you will notice that it looks a little wet. It will maintain the wet finish look permanently. If you apply a topical sealer when your grout is only under 30 days old, then it will discolor the grout or make it look awful. A penetrating sealer, on the other hand, seeps into the grout. It usually does not affect the appearance of the grout and you can apply it only 72 hours after you have laid the tile.