It has been too long. Now you are refreshing my memory. You have to control the voltage precisely to get silver without harming the fix, otherwise overvoltage causes the hypo to decompose. Also, with acidic fixes, the fix is probably going bad anyhow from oxidation by the time it is so well used that there is enough silver to warrant reclamation.
This is why I seem to remember that it is suggested that the fix be discarded after the silver is reclaimed.