Red spot in gold barrel plating

I had a big problem about Gold barrel plating on Fe material please advise me as your possible,Our process is Electrocleaning --> Acid dip --> nikel plating --> Au Strike --> Au plating After that I found the small red spot on plating area and I thought in the nikel process was no good,but after change nikel chemical its still happened.Now,i don't understand and no idea to prove and preventive this defect.Could somebody advise to me as soon as possible. Thank you

I believe the red or orange dot you are getting id the complex nickel tetra cyanide. Try use the cation -ion exchanger to remove the nickel cation. The gold cyanide complex will remain since it is anion. If not you can try to treat the bath with poly sulfide but it stink like crazy though. Good luck