Mark

I have just grouted the Brazilian slate tiles and it was a disaster. The grout dried instantly on the tile surface and I had to scrub it off. I sealed the tiles first as follow;
I washed the slates 3 times and let dry for a day before applying matstone tile sealer, 2 coats with clean cloths and all was fine.
I buffed the sealer as the instructions and left for 3 days before starting to grout
please help me