I have an indoor enclosure for my russian tortoise and I use Reptibark as a substrate. My tortoise pees quite a lot and I have been spot cleaning his feces daily, however, it hasn't been smelling pleasant as of late and I was forced to take all the substrate out and clean the enclosure. There...
No, it's just that if it's not naturally brown, the chances are it's a harmless weed. If your turtle hasn't done anything strange by now, just don't worry about it.
It doesn't look like one of the more common poisonous weeds; it's not nightshade. I don't think you should be worried if the turtle hasn't shown any symptoms of poisoning.
Personally, my russian took about 2 days to start eating and drinking. Perhaps soak him to keep him from dehydrating. My tortoise was wild-caught and I think those take a little longer to adjust.
Are commercial foods like the all living things tortoise pellets actually good for a tortoise? I read in the ingredients that ground corn was a large part of it, but I don't think corn is a healthy food for the tortoise (russian).