I actually agree with both previous posts....I would remove that middle rock, but slightly pull the two islands apart. Once they are covered with coral being that close, you won't even be able to tell it is two separate structures. I would also continue to increase the height in the left island, adding one or two more rocks to give the highest section more bulk for coral placement. Currently, with the exception of the high point on the left, you will have the same lighting levels across the whole structure.