Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Your woods are too far apart. Move the back one a little closer to the middle back but not centered, just move it a couple of inches.
Try front one be turned around so it points inward. Not sure if that is the answer.
Alternate: Put both sorts of wood near each other as if they are several trunks coming out of one root, or as close as possible with those anchors. Put them on a bit of a mound, and use the rocks to help stabilize the mound. This does not have to be in the center of the tank, but here is how to figure out where to place it:
Draw a tic-tac-toe on the floor of the tank. Put the center of the mound on one of the rear crossings.
A cube tank is one of the few that can be set up with a symmetrical layout, that is, everything centered. I do not happen to like that layout, but it is possible. Better if things are off center, but not much. About 1/3 or 2/5 is good.
Either way, move the main rocks in closer to the wood, so they look like the tree is growing from a niche in the rock.