Any advice on using this stuff.
Ive read not to use it if you have used a coloured grout because of the acid. Ive used mapei ultra grey. The tiles are large tiles with rows of rectangular mosaics in them. They are stone effect with matt finish,.
There is a residue from grouting on the tile face like your normal surface dust all over them which will not come off. So as one of the other forum guys recommened this is the stuff which will work..
My concern is, if it causes problems with the coloured grout, then its not like I can just wash over the tiles with it, because there are grout lines everywhere..