White patches on rhodium plating troubleshooting

Hello,

We are getting white patches on the rhodium plated jewellery in gold
10K & 14K as well as silver. Rhodium used in RodhunaTD voltage 3-4V
bath temperature 50-60degrees Centigrade. Has any one faced this kind
of a problem. What are the remedial actions to be taken?

Thanking you all.
Umesh.G.Chavan