I think they are pretty active. They have regular meetings and events. I think they are heavily involved in the Brewer's Jam. I am not a member, though. So I don't have any first hand experience. Too busy to be an active member, so I haven't bothered joining.
I haven’t, but this may give you an idea of what you are working with. From a local club.
http://knoxhomebrewer.com/wp-content/uploads/2018/08/Knox-area-water-analyses-080118.pdf
I use the Kroger Home Sense Multi-Purpose Oxygen Cleaner, a generic oxiclean. Works great, but I have had the white residue from leaving things soaking too long. Starsan will remove it, though. As will any mild acid.