It depends what all is in the well water. Typically tap water has things in it beyond the chlorine/chloramine that are bad for fish. Sometimes it causes problems over time, usually not right away. What did you test in your water? Do you know the TDS
Not sure where you are, but in my area, almost every grocery store and gas station has one of those big water dispensers where you bring your own bottles to fill. They use carbon and RO
and it runs about a quarter a gallon. TDS
is usually around 003. Not perfect, but way better than my tap water. There are also a few stores that strictly sell water. I've never tried those though.