Newbie Seeking Advice on Water

Hello everyone,

I received an aquarium kit and am researching how to set it up. This is a
long-time wish finally coming to fruition, but I have no experience with
aquariums (or is it aquaria?). It is a simple 10 gallon rectangular glass
tank. I hope to be able to set up a nice freshwater environment for
tropical fish. I have read several FAQs and have borrowed several books
from my local library. However, I have not found an answer to this
question.

My house is supplied with water from a very old well. I have the water
going through a filter system and a softener, however, the raw water is very
bad (iron bacteria, causing rust stains on everything, odor/taste bad) and
these do not get rid of it all. They help for our (human) purposes, but we
still buy filtered water from our local grocery store for drinking and
cooking. The purchased water is municipal tap water (Detroit, MI) that is
filtered through a system at the store (Culligan system, several different
filters including activated charcoal, reverse osmosis, and ultraviolet
light).

Which water would be best for me to use in the aquarium? I am concerned
about the well water having bad things in it, particularly the iron
bacteria, but also concerned about the store water being too clean.

Any advice would be appreciated.

Thank you.