[sswee]

Are the parts that anodize always out of the same tank?
Are the cathodes wired in parallel also?
Is the tank temp rising in one tank and not the other?
Is the electrolyte in both tanks from the same mix?
How close are the parts to the cathodes? Especially the ones that had black streaks.

Since you're in a pinch for time, may go with a 10 or 12 gal clear plastic storage bin to eliminate a few variables. I take it that you had no problems with a single tank, the problems started with the addition of the second tank.
SS