Hello fellow reefers

[Montaquelaveist]

Hello to everyone need a little help I just purchased this so called deep water acro and was wondering if anyone knows what the real name is for this piece and also how low can I place it it's about half way now and I a dim part of the tank thanks in advance for any help guys and gals sorry for the grainy pic took it using my iPad but it's smooth and currently pale bluish white