We had our kitchen floor tile professionally installed a few years ago and the grout has been a constant problem. The grout keeps cracking and coming out. We had the company the originally installed it come back out and fix it for us once and they said well maybe it was a bad mix. I suspect it was the mixer and not the mix. Question can we take all the visible grout out between the tiles and replace it without harming the tiles and their stability. None of the tiles or coming up as far as we can tell. The grout they used did have sand in it.