There is another alternative ...

There is another alternative - do nothing.  Many thousands of people live with iron in their water - there is no health issues.  You may just need to clean out small valves from time to time, and flush out storage tanks once per year or so.  We lived with such a situation for about 30 years, in fact it was the best tasting water we ever had.  (we have now moved to a new smallholding where the borehole water is quite hard - and we miss our old iron rich borehole.