I'm going to make a guess here, but when I had amalgams still in, I developed a stomach ulcer (bleeding). I beleive the basis for it was Helicobacter Pylori (often called H. Pylori). It was very painful.

Through some personal experimentation, I have come to believe that H. Pylori caused this issue with me and that it is facilitated by the presence of mercury. When I took a natural supplement that kills H. Pylori, the pain completely subsided within hours and stayed away for 24 to 48 hours.

(Perhaps the algin is irritating this in you, or mercury that is accumulating in the vicinity of the algin is doing the same.)

Here's what I took:

Gastro-Health

Permanent Link:

Gastro-Health

Hope this helps.