Hi Debra, you should stay away from all compact and coil UVB's (those are dangerous) and also the Repti-Glo 10.0 strip fluorescent bulb as there have been some problems with that one. If you live in the US, the best strip fluorescent you can buy is the Repti-Sun 10.0 which you can get here for a very reasonable price.
http://www.petmountain.com/product/fluorescent/504983/zoo-med-reptisun-10.0-uvb-bulb.html This is about 1/2 of what you would pay in a petstore and they're giving a 5% discount now. You will also need a hood for it that you can get at Walmart, buy a regular fluorescent light, pop off the plastic cover & the bulb that comes with it, put in the UVB and leave the plastic cover off. The fluorescents need to be replaced every 6 months. Not sure what UVB you've been using but at a distance of 13 to 15", he's getting no benefit from it. Is it a long bulb or a swirly type UVB?
If you have a 40 gallon tank or larger, you can get a mercury vapor bulb which gives off heat & UV rays. If you want info on those, let me know.
It's important that your beardie get calcium 3 days a wk and vitamins supplements 1 to 2 days a wk and you can put that in water, diluted juice or babyfood (like applesauce, squash, garden vegetables, etc) and offer by using a plastic medicine dropper by putting drops on his nose for him to lick off. Since he's eating crickets, you should be dusting them 3 days a wk with the calcium and 1 to 2 days a wk with the vitamins. Adults should be eating about 80% greens/veggies and only about 20% live feeders because otherwise liver or kidney damage could occur from too much protein. How many crickets has he been eating a wk? Here's a site that shows the best greens to feed:
http://www.beautifuldragons.503xtreme.com/Nutrition.html Offering a variety of them seems to keep them interested and you can even put a little of the fruits on the list on the top to entice them occasionally. If you have any other questions, let me know.