Thanks for the input Mongo! We try to be very diligent with the installation too. And SpectraLock was absolutely great both immediately after installation and few years later. Unfortunately, we will start our bath reno shortly after that kitchen backsplash project, so there will no be enough time to get a long term test for Dimension grout. Oh well, it could be actually because with our full time job and other activities, our remodeling will not be fast. What do you think about the aesthetic effect of this grout? Is it worth the hassle and the extra cost? I did not see it in person, only on pictures..

There are glass tiles that are clear without color cast. I am looking at a sample now that is made by opaque, clear, and crackling 2 x 0.5 inches mosaics, no color cast on any of these tiles. It is normal to obsess over the little details, actually I think it is a necessary process when making decisions. In a remodel, not only we spend money, time and energy, we have to live with the consequences. The part I do not like is I do not 2nd guess, instead, I 32nd guess every decision I make. It drives me crazy.

One thing I learned about epoxy grouting river rock: you want to make sure a line is left at the edge for caulk (color matched) to be put in right at the plane change, or you risk cracking at the seams (I've heard of regular tile breaking, rather than the epoxy grout breaking, but in our case, I guess the rocks were flexible enough that the epoxy grout cracked instead). It's a bit tricky aesthetics-wise, because there's no natural break as there would be with a row of tile--we're just cutting a teeny groutline-sized line in and we've made sure to color-match the caulk to the grout very carefully. The lack of natural break with the rocks is why mongo has shown that he puts a row of tile around the outer edge of the floor of a rock shower--it provides you with a clear place to do the caulk plane change. But if you've already got the rock down, and no ability to edgeit, just make sure that there's a groutline's worth of space left around the outside and that caulk is put in there, rather than grouting all the way up to the beginning of the vertical.

Hi there, I came back to update this topic. No, there is no way it was mildew. The apartment was extremely dry, actually, during the winter months, and the discoloration went all the way through the grout. The Starquartz company has been a nightmare to deal with. They sent a nice representative out about a week after I posted, who immediately promised to send me new grout and $500 credit for my contractor. Well, guess what? I emailed and called for 5 months (!) and nothing ever happened. It was an empty promise. Finally, I found out from my contractor that another person had the same problem, so we spoke, and found out that others also had this issue. It was DEFINITELY a quality control issue on the part of Starquartz company, as there were several of us affected by the "bad batch" as a rep referred to it. The long and short of it is that the tile store that my contractor bought the Starglass grout from (Artistic Tile in NYC - good place!) issued me the $500 rebate and charged it back to the company, and then they forced Starquartz to send us the promised 3 buckets of diamond white starglass grout. The only problem was, after 4.5 months of waiting and calling, we HAD to get that bathroom done so by the time they sent the 3 replacement buckets in late June/early July, totally out of the blue as Starquartz had not contacted us about it, ever, we had regrouted about 3 weeks earlier with regular cement grout. (The contractor had dug out the bad grout many months before in anticipation of receiving the promised replacement, so the bathroom couldn't be used for all those months.) Caveat Emptor!