The protodermis of a Toa seal was harder to break than protosteel.
Six different Toa with the same elements as those who formed a Toa seal could destroy the seal.
Six Toa with different elements from the ones who created the seal could not destroy it.
All six of the original elements needed to be used to destroy a Toa seal.
The Toa seal formed by the Toa Metru around Teridax was more like a solid sphere compared to the cage with bars the Toa Mata formed around the Bahrag.
Turaga couldn't form a protodermic seal by combining powers like Toa could.