There are some cheap clamp style led lights that will help keep the light off the water level and growing algae. I use this one on my 7g tb tank.
http://www.ebay.com/itm/BeamsWork-Aquarium-33-LED-3-5W-Double-Power-Clamp-Light-Beam-30cm-40cm-/181040505790?pt=LH_DefaultDomain_0&hash=item2a26dae3be
This one sits 5" above my water level and It grows fissidens, moss and dhg fine.
A lighting hanger soiunds like it might work for ya as well.