First do I need to remove the grout and regrout? Or can I just apply fresh grout over the old? Only a few spots here and there have lost a little surface grout of flake thickness. This flake thick loss is not visible after I clean them.
Can I scrub clean the whole wall and apply some form of polish then a sealer to restore the tiles? If so what brands should I get? My water supply is very hard and I think the dullness is from the film of soap-mineral deposits.