Larry:

I think your problem is likely the length of your first rinse chamber.  The
high pH, the high level of ammonia, and the length of time it is exposed is
your big enemy, and with due respect to my honorable comrade on this forum, I
do not believe that splitting the feed will have any significant effect.

Your rinse chamber is about 3X as long as I am used to seeing for a first
rinse.

You could use tap water as a first rinse, (20 years ago, everybody did) and I
suspect it might not be as bad as you suspect, because the real problem in
waste treatment is not the amount of Copper in the rinses, but the amount of
chelate, that keeps the Copper in solution.  The difference between using tap
water vs. using etch replenisher in the first rinse is only in the amount of
Copper introduced in the waste treatment system, the chelate (ammonia) levels
will remain constant.

Suggest you TRY using tap water in the first rinse, as an experiment, to see
if it solves the problem, then, figure out if you want to keep the change
permanent, or simply shorten the first rinse.

Rudy Sedlak
RD Chemical Company

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