Iron in water is in 2 forms: ferrous and ferric. If you can't see it (water is clear) then it turns orange with exposure to air it's ferrous. Sediment, carbon filters will not remove it. The systems that aerates the water and then passes it through a removal medium is effective. The media needs to backwash every 2 days max (depending on volume used).
Watts makes a media called filox that works and as long as it is washed regularly it lasts.
I don't know if it comes in a small system. Check Watts water quality.