I need help in Calamity Mod about the Sunken Sea!

[timeless slayer]

I was spreading the crimson in my corrupted world when I had an idea. I wanted to make the sunken sea under my regular sea. I did a lot of work but mobs were not spawning. I already got the requirements but I don't know why until I looked in the wiki. It says that a player-built sunken sea will not generate mobs but is there a way to get mobs to spawn in a player-built sunken sea. Let me know soon!