That should be a simple reef..... anyway theres no way you should keep 3 BT in a 2 footer, not even small ones . IMo witha tank that size, you should not think of keeping any tangs, anyway they are much more nicer and smaller reef fishes out there.....
And since its only 1 day, i think your BT are still alive in your atnk squeezing themselves in some caves.....
And pls remove the tangs sorry for offending you if i ever did, just that i care for the welfare of the fish