Complete bullshit.
The FIRMANENT separates the "waters above" from the "waters below".
Revelation 17:5
"Then the angel said to me, “The waters you saw, WHERE THE PROSTITUTE SITS, are peoples, multitudes, nations and languages."
"And he said unto them, Unto you it is given to know the mystery of the kingdom of God: but unto them that are without, all these things are DONE IN PARABLES: That seeing they may see, and not perceive; and hearing they may hear, and not understand; lest at any time they should be converted, and their sins should be forgiven them."
There is no firmament, it's parable.
Have you ever wondered why the only time the bible mentions the Nicolations is in Revelation?