My living hall grout is white. Over time it turned yellow and some parts black . Some still remains white under area where we cannot reach with our mops. I would say it turns yellow and black due to mopping. When we mop we use detergent and water of course.

How do you suggest i do? Dig out all the grout and buy your sufar pores C? That is a lot of work. Should I mix the new grout white powder only with your product without water to have better result or mix with some water and what is the concentration or ratio?

I also see you have another product that removes stain. Can I use this product to remove the yellow and black stain on the grout and then apply the water repellent?