I been using the domed clip on light from home depot(without the dome shield)along with a 54 watt par38 LED bulb.been using it for about 10 years now..grows macro algae like crazy.i think I paid $35 for the bulb and $12 for the domed clip on fixture
Here's the link for the bulb
This 54w reef spot light with a very unique design, whole aluminum housing, making good heat dissipation. And 90 degree lens increase the PAR and LUX value, also get a great coverage over tanks. 54W Specifications.