For generating colloidal silver, I have found that distilled water works fine. I would never recommend using tap water for generating colloidal silver because of the inconsistencies and impurities in the water...unless looking like a smurf appeals to you. I have found differences in distilled water interestingly. Walmart brand stinks for creating CS. Kroger's works great! Don't know why. I am consistently getting 15-20ppm CS.

I would also stay away from salt solutions. While you can produce a CS batch very quickly with salt solutions, you run the risk again of creating unwanter silver solids.

My process for creating CS is quite simple. I use a 48 oz container, fill it up with distilled and run it for about a day and a half. I start the next batch with at least a cup from the last batch (helping to overcome the poor conductor issue.

So far so good.