Those who are mercury toxic can also get a strong reaction to high sulfur products due to a possible increase in mobilising metals. I had this very strongly when highly mercury toxic, so much so it was at times, intolerable until I chelated enough mercury.

better not to overdo sulfur foods/supplements if one is high in mercury and it's causing too many reactions. Sulfur is healthy and some really need more than others, but others may find it shifts the metals around too much. Maybe better tolerated as mercury is further chelated out as in my experience. I used to have to be careful having too many sulfur containing foods at one sitting (e.g. eggs, onions, cabbage etc). But after I reduced the mercury more, I was able to have any amount at all.

Im not sure about algin. I hear this just helps absorb mercury in the gut etc and can help with symptoms. I don't know of it being a mobilising agent.