I did some more reading and wanted to bounce what I found off you guys. A European study stated that vaporization with oxalic acid is most effective when applied from the upper chamber. I was thinking of building a small spacer with a hole to apply the vapor. Also, the study said that if you are using a propane heated vaporizer that you have to account for the material that stays in the pipe so more than 2g is needed to properly treat the colony.
Has anyone else seen or heard this information?