I'm not familiar with the colors, so I'm no help there. Make sure you let the sample dry at least overnight. Grout tends to lighten up as it dries, sometimes quite a bit.

why don't you use mapei grout.....I've used 3 of their 37 colors...matching caulk...I think the product you're looking it is commercial...like around swimming pools/fountains/etc...cousin to Laticrete...it may have fewer colors. The people at Daltile encouraged the Mapei grout ......I brought up Laticrete. with the tech people at Daltile., and this was for tile around tub.....".not necessary " ,I was told....backsplashes aren't ususally drenched with water....check out mapei for colors.

Second the Mapei grout. We used the flexcolor white. Pricey but just what we wanted. Cheaper on Amazon than ordering local. A gallon did 40sf of 2x6 bricks with some left over for maybe another 10? But, we had never done it before and probably wasted a lot. Love it.

I love mixing paints - as in painting illuminations, but that experience would make me super hesitant to be mixing grout colors. The first issue is making the right amount. It absolutely has to be the same for the whole job as you can never recreate a "Let's add a bit more of this" color if you run a little short. Another problem is whether or not you're going to get the color you're looking for. A little of this, a little of that, maybe a tad of this other thing. Will it ever be right? Will you know until you use it and let it dry? Maybe if you treat it as a rigid science experiment and measure out so many grams of one and so many grams of another it could be reproducible for the day of install. Maybe.

So, how about that Mapei (or other) grout?

Suzanne, yes, I would have to mix up extra just in case. And absolutely I would have to measure it carefully and try it on a sample board first. Thing is, after extensive research into the various grout options, I really want an epoxy grout, and I'd really rather use the Spectralock. I'm doing this myself, and I'm not a professional tile setter. Spectralock has had the most consistently favorable reviews (from what I've been able to find online) of any of the epoxies. I would have thought a greyish beige would be easy enough to find, but apparently not. Also--I now have two minis of the Spectralock epoxy, and I can only return one because the other was opened for the sample board. This stuff isn't exactly cheap, so if I can make the color work using Spectralock, that would be my preference.

Thanks for the comments. The Spectralock is actually not a commercial product. Used to be available at Lowes before they switched to Mapei - they switch every couple years, it seems. It is designed for regular tile installations, not specifically for pools or fountains.

Yes, I let the sample board dry over night. It's been 3-4 days now. Still pink. Ugh. Online reviews for Mapei have not been great as far as grout color matching the samples, so I fear another issue there with having it not look like it should on the sample board. Some of the reviews have also indicated it's difficult to clean the haze off the tiles. Switching brands also doesn't help my having $39 invested in one of the Spectralock minis that's already opened. If I have to switch brands, I will, but I really would like some feedback on the Spectralock colors first to see if that can work.

FWIW, I'm not concerned about mold and mildew on the backsplash. This is not like a tub or shower after all. What I am concerned with is food stains - spaghetti sauce, red cabbage, etc. This will be a relatively light grout color, and there are plenty of foods that can splatter and stain.