Please watch the videos.
Please note:
It doesn't matter how deep or shallow the hole is.
Please do not mark this as a duplicate and claim it is resolved, the post you might think are duplicates are not supposed to be there (I am a new user and I was trying to figure out how to use this platform).
Bubble collums require all source blocks to work. You are placing water at the top of the collum and it is flowing down the hole. You would need to place a bucket of water at each block as you come up out of the hole to make this work. (There are other methods for creating source blocks of water in collums too)