We have periodically had trouble with iron, sulphur, and manganese in the well water here. The first filter system I had used potassium permanganate - messy nasty stuff - and I could never figure out how it could be removing excess manganese. It was also very annoying if you ran any water during a backwash it would pull permanganate into the system and taps would run purple for awhile.
Anyhow, we eventually switched to a 'berm' system which doesn't use any chemicals. The water is great tasting but I was worried about high manganese and have seen the bad effects it has on plants especially in small containers when it builds up over time. But recently we tested and found the pH of the water to be neutral, and afaik all minerals are now filtered to acceptable levels. It may be that the patch of bad water has been exhausted too - the filter was clean last time it was done.
My Mom has one of those filters that takes salt (I guess it's just a softener!) and it really worries me that she is adding sodium to her water!
I mean it's really not good for someone with high blood pressure, I guess.
