Plating steel and cast iron: Rust removal/pickle

[tokay]

Trying to plate some chain and later on a couple of cast iron pieces. The chain was once plated but after many decades was totally rusted off. I bead blasted the chain to bare metal and then put it into a vibration polisher for several days until it was smooth and shiny. There is a lot of pitting but it's not a big deal since this is all for antiquing anyway. I etched in pickle #1 for 15 minutes, and then in degreaser (wrong order I know) and then washed in running water for a few minutes.

I noticed that in the rinse water, the chain had developed a slight rusty tint overall in just a minute or two. I used lukewarm water, which is how it came out of the tap. I wiped the rust off the chain, did a quick dip in clean water, and plated it. It took ok, but the pitting didn't seem to plate with flash copper. It left dark holes--I thought the copper would plate into the pitts instead of leaving them black. Is this a rust problem?

Most important problem: How do I rinse anything in cast iron or iron steel in water without the danger of rust developing? Should I only use cold cold water (since iron rusts very fast in hot water)? How long should one rinse after SP degreaser and pickles? Is there a ratio (bath time to rinse time)?