Excellent advice however I clean my filter sponges in the water I have taken out because they are so dirty that if I left them in the tank I could never remove it all hope that's ok
I have well water and my dad says it has natural minerals and no chlorine, I mean I have declorinator but don't usually use it. Been using it for two years and seems to be fine. Any concerns?
The only concern might be heavy metals, which a dechlorinator would deal with, or other contaminants.
Are you drinking the well water? If you are, then it should be fine for your fish as well as I assume it will have been checked for pollutants, if it's being used for human consumption.