Broke, I had forgotten about another possible cause of your blackener problem. See this other post:
http://www.caswellplating.com/bbs/vi...ight=blackener
I too have the "CopyCad & Zinc Blackener, New Formula". The bottle labels says mix at 9:1, but apparently this is not correct, it should be mixed at 4:1. If you're mixing at 9:1, then the solution is too weak.
It would seem that the earlier printed manuals, and bottle labels, are incorrect.