Looks like a good start, pleasing design. Nice to see you didnít totally over do soil layer.
Iíd move filter over bit towards center so itís output sweeps by wood instead of being blocked by wood. Many people underestimate how important good flow patterns in tank and across substrate bed is for keeping a healthy tank.
A nice dark backdrop will help dark filter from sticking out as much which is why I figure you hid it behind wood.