Orange roots??????????

OK I over fed my plants with bloom feed and after a week of flushing the system 2 bring the ec back down my plants are showing a slow but steady recovery. I have however noticed that the roots in 2 of my plants have started 2 turn orange.

My question is does anyone know what might be happening? Is this just die from pumping water through the clay pebbles or something more serious?

root rot you need to run proxcide throw your system

Should I cut of the diseased root or will proxide clear it up?