Hello, Mike, How many consecutive re-brewing cycles do you make, and brings it to a halt? Conductivity measurements might not be a sure guide when the product is a mixture of ions and particulates. Maybe we should return to the old-fashioned ways of assaying silver: precipitation by dilute muriatic acid, followed by re-dissolving by dilute ammonia. Granted, a burette and burette stand cost a significant amount of money. But pipettes can do the job too. And they are inexpensive. Muriatic acid and ammonia can be bought cheapy at the hardware store.
Best wishes, Matthew
