If the current is too high, you can cook the fixer and release Hydrogen Sulfide which will ruin the fixer and is bad for your health.
Originally Posted by Joe VanCleave
We use the big rotating drum silver recovery units from Rotex in nearby Springfield, Ohio.
Here is the model we use: http://www.rotexsilver.com/series_2500_4000.htm
I am certainly no chemist, but it is easy to tell when the current is too high; the smell of rotten eggs is a quick alert to lower the amperage.
Somewhere around this heap of books and cameras, I have a set of plans from Kodak in the 30's or 40's to build your own silver recovery unit with a few bits of wire, a stoneware tub and (basically) a battery charger. Been wanting to do that for a while, so I will start digging.
Ironic that I am awash in a sea of information, but I can't locate anything to save my life...