Re: 4000 PPM "single atom" silver? Test your colloidal silver for chemicals, here is how:

Many things which are heavier than atoms can stay suspended in water - take the particles in true colloidal silver for example.

Would you have us believe that everything which is heavier than water will descend to the bottom of the feet?  The body is not a one way elevator and a great many heavier-than-water items travel in the blood stream to the feet and back via the circulatory system.  Just ask your friends and doctors in the science community.

In the colloidal silver community, you could educate yourself a bit about the issue of silver being a heavy metal and the mistake of trying to lump all heavy metals into a toxic category here:

http://www.silvermedicine.org/silver-heavy-metal.html