The answer to your question is more than likely, yes, but also likely iron/ferric chloride from improper chlorination.
Chlorine is very corrosive. Pouring chlorine into a steel alloy well will cause more harm than good. Chlorine should be diluted in large quantities above ground, not more than 70 ppm active chlorine, then the well and pump should be flooded, allowed to soak, and then flushed. Chlorine is for disinfecting water, not for cleaning! If your well is not doing good, don't disinfect it, clean it with WaterSOLV BC. Once cleaned, then properly disinfected, you'll have a healthy and longer lasting productive well.