Don’t worry—and don’t add water—if the grout seems a bit thicker after 10 minutes. Mixing grout isn’t terribly difficult but may take a bit of experience to get it down perfectly.
However, if you want to avoid mixing, Yodice recommends using a single-component grout like Laticrete Spectralock. “The ...
Based in LaGrange Park, Illinois, they offer both colloidal and paddle type grout mixers, as well as a variety of grout pumps, including piston, plunger and progressing cavity. Outputs range up to 45 ...