your hardware all blends in really well...except for that filter outlet pipe! Hope you don't mind me saying, but I would keep the moneywort and have it all in that corner to cover that pipe, which keeps drawing my eye across! Or something else tall there if not, to cover the pipe and add more dimension to that rear corner behind the wood?
I love the background; I am painting my 5' newcomer a slate grey rear glass as I love your contrasts...have you got reds in those plants? I have an Alternanthera cardinalis in my cemetary tank which is doing well; ultra low-tech with just a clay fert ball at the root; likes an alkaline pH; ochre-brown upper leaf surface, a red/purple colour underneath, grows to about 20cm I have read...be a nice colour in there perhaps?