Turns out the scratches could be removed with more scrubbing and I got the grout 80% cleaner looking with Zep and a grout brush. However, there is some permanent wear and discoloration that will never come out. So, the shower floor grout still needs to be replaced if I want it to look new again.

I was considering getting expoxy grout for the shower floor, but one contractor says he doesn’t recommend it for white grout, because it will eventually turn yellow and not be repairable.

Is there a better material for white shower floor grout or is there another color of expoxy that will work better with the shower base without clashing with the grout color on the walls?

If the grout is still in place and holding, I would leave it and use a grout colorent on it. If you want to regrout, you need to remove all the old grout. You cannot grout over the top of the old.

I understand the grout needs to be removed. i will be hiring someone to do it that specializes in that work.

However, if I’m going to the trouble and expense of regrouting, I think epoxy grout would be best so it will last the life of the tile and never need to be redone again.

If you have white grout pls try Oxi Clean Scrub with bleach. I apply on my white grout generously and just leave 30 min or more. Later with wet soft sponge I wipe/ Clean until oxi clean is removed. Works always for me. I don't Scrub. Just check first if that is not going to discolor your tiles. Mine are white. It also works for me if the white caulking in shower is effected by mildew.