Current thought on colloidal silver, as well as all colloidal solutions, is that particle size is the more determining factor in effectiveness. With smaller particle sizes comes increasing bio-availability, hence greater effectiveness. In other words, a 10 PPM solution at .001 to .004 micron may be just as effective as a 100 PPM solution at .01 to .04 micron. PPM by itself is a measure of the weight of silver in the water and NOT the particle size. Unfortunately, the only method of which I'm aware to determine particle size is through scanning electron micrograph. Not exactly cheap.
Any discussion of PPM is meaningless without a corresponding measure of particle size. Under the circumstances, it would be safe to assume that PPM could be used as a general guideline, however, the body's reaction should be the ultimate factor in determining dosages of a particular CS solution. When giving dosages, the user should allow the body to be the ultimate judge of proper dosages.
Offered by Michael.