I have my doubts about perlite releasing fluoride. Here is a web site for
According to this organization, perlite is essentially an inert silica
material (here's that silicon beast again - silica is silicon dioxide, also
known as glass, quartz, etc.) that is industrially expanded by way of a
small percentage of water in its peculiar mineral form.
Fluorine-containing materials probably way too expensive to offer as bulk
fillers. If they give off fluoride ions in any appreciable quantity they
would be better utilized as a raw material for obtaining fluorine.
Sorry to quibble, but that's what you get by having a chemist on your list.