Can a Bloat Dispenser and Multi-Purpose Dispenser be used in the same trough?

Yes, a Bloat Dispenser and Multi-Purpose Dispenser can both be used in the same trough at the same time.

However NEVER mix those elements together in the same dispenser.  If other elements are mixed into the same dispenser as bloat control material a thick gel will result, which will block the outlets in the dispenser. As long as the bloat material is in its own dispenser, it will work fine.