I agree, with busy bee. Love my turbo! I do a lot of tile & grout... as stated already you can't be too careful with the acids, however they can be your friend if used with care. I have a large plastic storage container on my truck with several different colors of grout, this always comes in handy as you will blow out a small piece of grout from time to time. Between the grout and the grout stain I carry with me I can usaully make a small repair in a minute without the customer even knowing. If there are pre existing pieces of grout missing I can repair as a added service. My point being, if you are going to clean tile and grout it is a good idea to learn how to do grout repairs, or even better, know how to replace a craked tile. Just like carpet repairs, they are not that difficult once learned. Just one more very important thing to keep in mind, if tiles are cracked or grout is missing it usally indicates a bad installation, so you should not offer a gaurentee or make the problem floor your problem. If a tile cracked because a 25 lb frozen turkey fell on it, that is not a install problem.