Supposedly, the Bentonite that the Great Plains company manufacturers contains what is considered the "optimum ratio" of sodium ions to calcium ions. This should give it the ability to "swell" which means that it'll adsorb the toxins more efficiently. Any quality sodium Bentonite should work well.
The biggest problem is that any type of Bentonite can cause constipation, and if this happens to someone using bentonite, they should stop taking it immediately.
Considering your problems, I would think twice before using any type of cleansing substance.