Thanks for the replies
Albert yes the before pic is after we cleaned using alk and acid + mini turbo for rinsing there was nothing that would bring that grout up looked more like hard blackish concrete than sanded grout I could have re grouted but she had no spare tiles around just in case we damaged one during the process even the walls were like concrete not un sanded grout.
I have been using Grout Perfect for two years now and I love the stuff it,s easy to apply and looks like grout not that painted on look. I like the stuff that much I became the Australian distributor which has taken off over here.
I have done a fair amount of public bathrooms and they still look awesome even after 1 year it still looks like I had just color sealed it but that's only after the maintenance mopping has been done with a neutral cleaner, I advice them to only use neutral cleaners from now on and a microfiber mop (damp not wet) for cleaning with than clean again with water to rinse not for the neutral cleaner but the wet soil still sitting in the joints or dry by a towel on a swiffer mop or use a wet vac. I also advice them on color choice and stay with a darker look like grey I have done some in white but it all depends on the person cleaning it if they wipe the grout lines dry with a towel after cleaning than it will look awesome again.
I go back to these jobs every 12-16 months for a quick clean with a neutral cleaner and turbo low psi for rinsing they always comes up great but if there,s areas that need a touch up of color seal than we do it there and than takes about 10 minutes or so to top up. I also give them a big discount on cleaning and extend there warranty if they use me every 12-18 months.
Craig