MOSAIC TUMBLESTONE WALL TILES DO I SEAL FIRST OR AFTER??????

[Nicetoseeyoutoseeyounice]

I am about to have my kitchen walls tiled in the tiny brick mosaic these are tumblestone. My tiler has said they will only need sealing once but they must be done. Well thats easy enough, but the lady in the tile shop says they must be treated with something else first (forgot the name) and then sealed, then about every 9 months give them a buff. Can anyone help with the correct procedure as these are quite expensive. She said if I seal before putting on this other treatment (forgot the name) then the tiles would go almost white and stay that way forever. Any advice would be greatly appreciated. Thanks.

 

[jefoss]

if the store says they need to be sealed, i personally would would use lithofin stain stop (available in good tile stores and a few bad ones)beofre i put them up and before grouting. better safe than sorry