With Hydroment, using their additive makes it feel like you're grouting with thinset. It'll drag from the grout joints until they're half empty, unless you don't clean the floor well, and then you have a whole NEW set of problems. With their grouts, I won't use any additives, and with most others, they're modified already.

Thanks, Mongoct, Bill! Appreciate your advice!

1. We cleaned the tile in the surround prior to grouting to a pristine condition, using no chemicals or acids.
2. We mixed the grout using only water--no Latex.
3. The backerboard is brand new, 1/2" Hardibacker.
4. The porcelain tile is imported from Italy.
5. About 45 minutes after our final sponge-wipe (after grouting the tile), certain sections have turned chalk-white.

It looks like a really bad case of effluorescence, but I doubt that any salts could have surfaced that quickly. Or could they? What else may this be? I mixed the grout WITHOUT any Latex admixture--just water. I mixed to a good consistency (not too much water). I let the mixture "slag" for 10 minutes. We applied the grout, troweled the excess, waited 30 minutes, then did a 75% wrung-sponge wipe down. Later, we did a final wipe with a 90% wrung sponge, then buffed with cotton terry cloths. A little while later, the chalk appeared! Most parts look perfect, a near-exact match to the manufacturer's sample chip. But about four feet of grout line, in various areas, now appear chalk-white. What gives? What should we do? Help!

If you're getting a chalky appearance, you're right-- it's not efflourescence. It sonds to me like too much water, one way or the other-- either the grout was too loose (or loosened up from wet tile), or too much water left on it after cleaning.

Thank you for the late-night reply, Bill! We mixed the grout pretty tight, and also wrung the sponge pretty tight, knowing that "too much water" was a common beginner's mistake. I was desperate, so I resorted to . . . reading the directions! The Hydroment bag said that if you're not using the Latex admixture, that you need to sponge the grout "several times a day" for three days, or else the "grout color will lighten."

But, the really weird thing is, a small test grout area I did (with the Latex admixture), applied onto a different, slate-like type of porcelain tile in another part of the house, dried to a near-perfect match to the sample chip. No haze, no chalk . . . perfect.

But, check this out: another test-grout I did (also, mixed with the Latex admixture) on the same type of tile used in the bathroom, but in another part of the house, resulted in the same chalk-white, residue effect! Both test areas, using the exact same batch, applied within minutes of each other--both tiles only two feet away from each other. How weird is that? I'm thinking . . . there's got to be some kind of reaction going on between the grout and that specific Casalgrande tile, right? What else could it be?

Not sure. I'd have to watch what you're doing in order to tell you what you're doing differently. Not to sound like a company rep, but my bet is that you ARE doing something differently, and that's the problem. I know for sure that mixing with water's not the problem. I can't even guess at literally the hundreds of thousands of feet I've grouted with Hydroment mixed with water and not had problems. Also, that's a bunch of garbage about having to damp cure the grout to keep it from lightening up. That's lawyer speak for if you don't jump through a bunch of hoops, don't come to us.

Ha! Thanks again for your reply, Bill. Well, we misted the surround last night and everything eventually dried to a consistent color, just a bit lighter than the sample chip. It's just that I love the color of this grout when wet! The next shade darker in the Hydroment palette is much darker (at least the sample chip is), so I'm guessing this was still the best match among their offerings. Maybe the Miracle 511 sealer will darken it up a half-shade (sealers tend to do that, don't they?) once we get to that point. Thanks for all your advice!

It's been my experience that grout usually dries to the color of the dry powder.

Terricks-- almost. Just a little more color to it.

Some good tips! Now . . .

My last BIG question . . . is there any color uniformity advantage to using a non-sanded vs. a sanded grout? I noticed that the Hydroment grout dried a bit lighter in areas where the grout lines got real thin--it looks almost white. Although the perception was partially due to a lighting effect, it begged the question . . . if you spread a sanded grout in too thin of a joint, is it possible that it's losing some of its colorant effect for whatever reason? And, my BIG question is . . . would a non-sanded grout be less susceptible to having its colorant "thinning" under those conditions?

Oh wait, I have ANOTHER last big question . . . the Colorfast-brand, colored caulk, matched to Hydroment's sanded "Heron Blue" grout, matches our tile EXACTLY. The Hydroment grout is a bit lighter and very slightly bluish in hue. In comparison, the ColorFast caulk appears to be completely neutral in hue (neither warm, nor cool), and is a slightly darker gray. It's a perfect match to the tile we have. Now . . . the question: what is the main reason you wouldn't want to use caulk in all the joints, instead of grout on say, a floor?

Thanks for any replies!

The ONLY factor that determines whether you use sanded or unsanded grout is the joint size. 1/8" and bigger gets sanded grout, and under an 1/8" gets unsanded.

As for caulking an entire area, I suppose you could, but I wouldn't want to clean up that mess!! You'll see when you go to caulk-- it'd be a nightmare to clean up.

We have installed 4000 sqft or porcelain tile (calcatta timeless) the installers mixed mapei grout with admix and the whole tile turned into a chalky, dirty tile that it is impossible to remove, the house looks horrible. We do not know what to do. Is it the combination of the grout with admix and the water that turned this porcelain into a mess?