John,
My understanding is that there is a difference between a chelator and a binder, and these words have been erroneously used interchangeably.
The metals will attach to the chelator (like DMPS, EDTA, and DMSA) and be dumped in the gut for excretion, but if they are not bound up in the gut with something like chlorella, they can easily be re-absorbed into the system. Chlorella has a "mop up" function in the gut.
There is not much evidence pointing to chlorella actually chelating.
Douie