I'm thinking the orange will indicate iron. I am not the metals expert on the forum, but if you'll go to the metals forum, there are many posts by Marie (mbar), who is probably the most experienced metals person on the forum, next to Ben. You should be able to get most of your questions answered by reading those posts, but if not, come back and post them. In the meantime, Marie should be stopping by soon and I'm sure can help you out, if that is indeed the problem.

Get the water tested if you can, and repost your results here--that will really help us zero in on what you need to do.....and just out of curiousity, take a trichlor tab and rub in on the orange on the steps, and let us know if it lifts the stain.

Janet