Now unless you are talking about monitors, Beardeds definitely need some sort of UVB exposure. If not, they cannot process the calcium into D3, and will get MBD. Also, the fluorescent tubes are junk and produce little to no UVB, and usually aren't bright enough to make for a happy Beardie. Now, the mercury vapor bulbs from ReptileUV.com are awesome, and you actually have to make sure they are far enough away from your animal or they could get overdosed on UVB(yay retinal damage...).

Go read on www.reptileuv.com and find the comparison charts for the fluorescents and other mercury vapor bulbs. The MegaRays are awesome bulbs and can't be beat for Beardeds and other sun-loving reptiles(not to mention they are cheap and last a LONG time).