A couple of questions about tiles.

[LKC]

Don't know if anyone can offer any advice, but I have a couple of questions about tiles.

 

Firstly, in our shower, it looks like the previous owners may have covered up some mould in the grout when the house was on the market. It seems to be coming through from behind, rather than growing on, if that makes sense, and I can't seem to be able to clean it off. I have tried the usual suspects (easy off bam, shower power etc), but I can't shift it. Is there anything else that might penetrate right in to the grout to clean it? Or am I going to have to remove the grout and re-do it?

 

Secondly, most of downstairs is tiled. The grout between the tiles is, I think, a cement-based grout (it is grey and rough). The gaps between the tiles is really wide (1 cm) and the grout is permanently filthy, where I presume it is pourous and absorbs muck. I looked in Bunnings and can see that there are grout cleaners and sealants, but I wondered if anyone could recommend one that didn't take 24 hours to dry. We have an open-plan downstairs, and it would be near impossible for me to stop the kids running around.