Lighting

The light that came with my 55g used tank supports two 55 watt power compact whites and two 55 watt blue actinic bulbs but has an additional light bar of some kind running along the back edge that I would like help identifying. It is a thin little tube and emits a bluish lite that almost looks like a black light but probably isn't. It is also wired separately from the main lights.

The light has no labels but the guy I bought it from said it was a coravue knock-off and that he was ...