We had our master bath remodeled last October. The tile floor in the shower is small hexagons with white grout and I’m regretting this decision, so many grout lines and already looks dirty even after cleaning. Our contrator said there was no need to seal but now I’m kicking myself for not doing it. So anyone know of a way to restore the whiteness to the grout. I’ve tried peroxide, vingar baking soda, zep grout cleaner and another grout cleaner. Also could I put a small amout of new grout over existing to freshen and then seal?