The "color" or "tannins" are checked by running the water at the well for a minute or two, and then taking a sample in a white cup or bucket, or clear glass, and IMMEDIATELY observing the "color" before the iron has time to react with the air ( oxygen ).ONLY if you have Color when water is first drawn, would you "need" the extra Tannin removal resin in with your regular softening resins.
