That color was thoroughly disgusting. Yuk!
I live off well water too, and we have 2 water softener/filtration systems in addition to the one built in at the well. (We share our well with 4 other houses so this water goes to all 5 houses. I think rather unusual, but that's how this area was built.) Our first night here using tap water stunk up the house, it smelled like rotten eggs. We called people (who, I don't know -- hubby did the calling) and they advised us to turn on all the faucets throughout the house and run for an hour to "clean out" the pipes. That did help tremendously. But the water still tasted funny, and we noticed after just a few weeks that our toilets, showers, sinks all were very yellow --that didn't take long at all. So we added the two water softener/filtration systems and now everything looks clear and smells wonderful.
Except our master bathroom sink. It still tastes like rotten eggs, despite the water being clear. It's the only water source in the house that smells like that. Our house is only a year old.