Sweet setup sunsetSPS. Very nice hanger.
mandm - Just to make sure I understand, the tank & light will be turned sideways when compared to the pic above.
If so, you could try to keep it simple & bend two poles like my 1st pic. Instead of them being 40" apart, drill & bolt them together to give you more strength. The 30"36" overhang will be a test but should hold.
Use a hanging kit like sunset has & you could either drill the pole or wrap it as I did.
Another thought: Using 4x4's could be very simple & once painted look pretty sweet. Lag the horizontal leg onto the top of a vertical post. Then cut a gusset (two 45's) & lag that to both pieces. You could then add a foot to the bottom for stability. Sand & stain for a finished look & secure to the stand.