The current flow in water depends on the conductivity. Distilled water has very poor conductivity but adding salts (ions) will accelerate the process and that's what determines the current flow. For such particular reason there should be a current limiter added while making silver colloid. What Beck device does is raising blood cells potential. This causes increased absorption and distribution of oxygen throughout our body also due to the blood thinning. The result is a better circulation and oxygen intake - very important, since many pathogens don't thrive in oxygen rich environment.