I would be interested if someone ran one of these without putting their feet in it. I have seen the same thing with some sort of electrolosis unit. Unless you use reverse osmosis water the minerals in the water are what turns nasty looking. How much comes out of your feet I would guess is minimal, defies logic really with session time etc. Even the detox foot pads are to be worn over night.?? I am open to anything but like to see some sort of evidence thats proven