A water softener water hardness minerals (calcium, magnesium) replacing
them with sodium improving the washing action of soaps.
Passing water through a potassium permanganate bed can remove small amounts
of iron and manganese .
Larger amounts of iron are removed by chlorinating which causes the iron to
precipatate. The water is passed thru a sand filter to remove the iron.
Then the water is aerated to remove the excess chlorine.
Do you want to end up running a extensive water treatment plant?