Unfortunately you can not just go over it. The grout must be scraped out. It is not easy and my remodeler husband HATES to do this and says it is a pain but the only way to redo grout is to scrape it out and put in new.

ST

Before you start carving your grout up...
Give this a shot (follow the link below).
Might be a little easier, and give you a satisfactory result.
As always, follow the instructions.

Here is a link that might be useful: Aqua Mix Grout Colorant

Good advice. You CAN go right over it with the colorant, once you've cleaned it as best you can. Also, once you've gone over it with the colorant, it'll be much easier to keep clean from then on.

Cool, I checked out the link. I can't find this though...what color is this colorant? Do they have a dark brown color?

Thanks for the fast replies!

We want to pull up this tile and redo all of it eventually..but until then, just having clean, dark grout would make me feel a lot better!

click on
color and coverage chart link
right under the pic of the bottle...

agreed, great advice.

after you color/stain your grout, seal it with aquamix grout sealer, and repeat this yearly or bi-yearly depending on the amount of foot traffic the area has, to prevent further staining.

Here is a link that might be useful: aquamix grout sealer

I checked the site in the first link. It says that the Grout Colorant "seals" - so why would someone need to use another product to seal it again? (Not arguing - sincere question.)

We always double coat grout sealer for customers ... even over colorant with sealer addative already in it.

also because joint seal doesnt last forever.

it needs to be part of a healthy maintenance routine.

For durability.

Kind of like why hardwood floor refinishers use 2 or 3 coats of poly instead of 1, even if its a poly/stain combo :-)

Although that'd be great advice for some colorants, sealer won't take over Aquamix's colorants. Just use the colorant and you'll be fine.

Thanks Floorman 67 and Bill! Now we know if we use a different product we might want to seal twice.

Since I didn't know if anyone would comment back here, I used the feature on the Aqua Mix website to ask my question - I didn't expect to get an answer the same day - especially on a Sunday! Here's what they said. (I love getting the "why" along with the answer!)
"The Aqua Mix Grout Colorant is a water-based epoxy that will seal the grout as it re-colors the surface. This epoxy based colorant will repel and NOT allow any liquids, acid, water, oil, or any other sealers to penetrate or absorb into the treated grout joints once it begins it's curing/drying process.
IF you apply a sealer to this grout after the application of the Aqua Mix Grout Colorant the new sealer will just pool on the surface. If a sealer cannot penetrate a structure it cannot offer any additional benefits or protection."

Here is a link that might be useful: Ask Aqua Mix

Why seal twice when you can do the job in one step?

You said you wanted to replace the tile anyway.
So as long as you are replacing the tile within the next 15 years- I'd say stick to simply applying the aqua mix epoxy colorant. Nobody seals epoxy grout- not even once.

Sorry - I guess it was kinda dumb to put it that way.

The "first" seal I was referring to was what the colorant itself does. And like the rep. said, that's all that's needed anyway.

I'll go away now :-)

But, if anyone feels like answering my peel and stick question, that would be great!

I didn't think anything was dumb- I just didn't want you to do more work than was necessary to get the result you were after.

Please let us know how it worked out; how long it took and if you were happy with the results. I'm sure others would be interested.

(post before and after pics if you can)

Good luck with the project.

Absolutely!!