Actually, you can put the basking holder in the front and an 18" fluorescent holder with the UVB right behind it, the long way. I had a basking & strip UVB on a 20 gallon tank & it worked fine. Once you get the strip fluorescent, you might have to make the basking area a little higher though, so your beardie can get 6 to 8" from it. Once you get the distance right, then you check the temps with a temp gun or digital with a probe & adjust the wattage of the basking bulb accordingly.