I'm not here to argue with anything you said but I have gotten rid of all of my mercury with clay, its all gone. I think tests on water are prone to error because the testing methods may not detect things that are present. I think if mercury (Hg 2+) is tightly bonded to an electronegative clay particle than it is probably harder to detect.

Doing chemical tests of any sort is problematic when we are dealing with mercury. You are probably aware that someone with high tissue Hg levels may have zero mercury in their hair mineral analysis. This result would lead us to believe that mercury certainly isn't a problem with theis person. The same sort of shifty results are probably seen when doing an analysis of bath water after a clay bath, for example.

I don't know much about ionic foot baths but I swear by clay baths.

-Colin