If I use the grout colorant products (such as Aqua mix that seems to be the preferred), will that be problematic in a basement? I am thinking the grout breathes now to allow moisture under the tile to get out. When I refer to moisture, I do not mean I have a wet basement, but I am guessing concrete will have vapor from its inherant nature of a slab on the earth below grade. It is a 1963 house, so I am sure they were not using poly vapor barrier before they poured the floor on top of the crushed stone.

So I guess my question, will the moisture trapped in the slab rise up and push the colorant off, or worse yet, will trapped moisture push up the tile (porcelain) by breaking the adhesive bond. Proper thinsets for porcelain were used because I made sure of that. The backs of the tile were also skim coated prior to laying.