"zinc interferes w/ DMPS binding Mercury, so don't give zinc on chelation days"

http://www.treatment4autism.com/After/chelation.html

I read somewhere else that DMSA chelates manganese and zinc, so it is probably best not to take manganese supplements as well during chelation rounds. In another place, it mentioned a study of rates where excretion of mercury was decreased when sodium selenite was given during DMSA chelation, so avoiding selenium supplements during chelation rounds also seems like a good idea.