Orange build-up on shower tile grout I submitted a similar question on a ceramic tile advice forum and got a couple suggestions, but thought I'd post it here also in hopes that some of you in the plumbing trades (or anyone else for that matter) can help narrow down what this problem is caused by, and how to clean and prevent it from coming back. When our contractor built our shower stall a couple years ago, he used QuartzLock-2 urethane grout on the wall and floor tiles...I think the color was "Wasabi", a kind of khaki green. Most of it still looks great, but over time, some of the grout color turns from that light green to sort of orangish. I assume it's soap residue or something like that, as most of it comes off with a vigorous scrubbing using comet and a scrub brush. However, lately it comes back quicker, and takes more effort to clean it. The enclosure is 3x5', and it's a double-headed shower, one on each end wall. One shower head rarely gets used, and that's the end where most of this orange film builds up, down low on the walls, maybe the lowest five rows. I'm thinking the build-up is happening because the walls on that end don't get nearly as much direct water spray as the rest of the shower. So my questions are: 1. Any ideas what might be causing this orange build-up? 2. Can anyone recommend products for cleaning this that might work better than what we currently are doing? 3. Is there a way to slow down or prevent this from recurring once we get it thoroughly clean? I have attached a photo that shows the issue quite clearly. Hope this helps! Note: Our other bathroom shower is fiberglass, and it also gets this buildup. The only difference is that it happens all over the lower part of the shower, not just in the areas that get less direct water spray. But it's still a PITA to clean! Might we need to soften up our water supply, and if so, how is that done? Any other ideas? Thanks!