Question Relating to 511 Impregnator Sealer

[Dolly Silvola]

We just remodeled our Master Bathroom using travertine on Floor, Marble on Counter Tops, and Cream Marfil on shower walls and has been sealed once with 511 Impregnator Sealer, but the floor still leaves powder on your bare feet when walking on the floor--should we give a second coat to all areas? The marble counter top and the marble around our tub does not appear that the installer sealed the marble, but if he did, would applying a 2nd coat on our part be okay? This bathroom project just got completed and has not been used yet, and worry about the application that was given only once. We would like to give a 2nd coat ourselves if it warrants -- please advise.