The plant bulbs from Home Depot that I've seen usually don't give off enough UVB. The ReptiSun 10.0 18" is what I use and it spans my beardie's 40 gallon breeder tank easily. Also, the long bulbs emit enough rays so that your beardie doesn't really need to bask in the UV because they give off UV rays for 20 inches. Don't forget to change the bulb every five to six months. The bulbs will start to not give off rays anymore around then.