Ok, right, it's greensand that uses the permanganate. Filox looked to be the most efficient stuff out there without pre-oxidation although getting a handle on expected performance is not easy. I've seen numbers from 5-15 ppm iron removal capacity for these systems. Does anyone have any reliable, real-world numbers that I could expect for the various filter media (BIRM, MnO2) assuming the following parameters:

no pre-oxidation
Backwash 8.5 GPM
pH 6.9
TDS 250
no sulfur
no manganese
no iron bacteria

My softener can pick-up some clear water iron bleed-thru (4 ppm ?)