Grout in my shower is all cracked, it was only installed 3 years ago, I'm looking to have someone remove all the cracked grout and put in new grout for me. I know the guy that originally installed my tile and grout purchased all the materials and used a grout type that you add water to, not sure what happened so I'm looking to buy the grout this time around, maybe something premixed. Any recommendations as to which brand to buy? My tile is ceramic 12x24 if that matters.