iron still in water after troubleshooting GE/autotrol 255

We have had an autotrol 255 valve with 440 control for 14 years now. We have iron in our well water but the softener has successfully removed it until now. Our water recently went both hard and full of iron. After troubleshooting the whole system, flushing everything, replacing the plastic tubing and fittings connecting the check valve housing to the brine tank, and renewing the resin and the activated carbon we still have iron in the water. The water is now soft and clear but takes on a slightly different hue after heating and the iron taste and slight iron smell is detectible.

After doing all of this I started to wonder if I was supplied with the wrong resin but on rechecking everything one symptom that persists is that the filter surrounding the injector remains clean as a whistle. In normal operation this filter fills up with iron residue requiring regular cleaning. The iron residue is now evident in the brine tank - something that did not happen before.

If anyone knows what our problem might be from these symptoms your help would be most appreciated