Hi thanks for any in site on this . water filter turns black if not changed befor 3 months have softer and filter after softner it never turns black so the softer must be removeing the manganese it has be removeing iron good have used every other bag salt has been morton rust defender i thing i need to get some citrus acid put in prevent i have 2.5 ppm iron ph 7.5 28 GPG so went 40 grain add iron been in service 1 year 64 grain softer dual tank fleck 9000 . the iron is clear water iron drilled 50 foot well artesian flowing in spring. only have some odor once while could be from black filter ? have that floating film on top water read somewere could the mag ? is there filter iron removal that would not need 2 part system like Thanks