So I'm in the process of having my bathroom re-done and the tile guys won't seal the white grout. I'm going to have to seal it since the grout is white and I don't want it to get dirty and turn different colors. Unfortunately, I didnt think about this beforehand, and pretty much everything in my bathroom has white grout.

1) Which sealer can I use that won't haze/stain glass subway tiles?

2) Which sealer can I use that won't stain porcelain?

How do I apply the sealer, with a painter's brush?

Here is my bathroom now (not completely finished yet, the bathroom floor needs to be grouted among other things.

{{gwi:1443537}}

Here was the before: