Yes, please buy a new Reptisun 10.0 T8 UVB and make sure his basking spot is within 6-8" of the light. UVB bulbs only last for 6 months, so you'd probably need a new one anyway, and I highly doubt that whatever you were using for your hermit crabs as a
UVB bulb will be appropriate for your Beardie! Bearded dragons are very specific and unique in their lighting and temperature needs, particularly their UVB needs, and unfortunately pretty much ALL of their bodily functions are dictated by them getting the appropriate wavelength and amount of
UVB light. So if you have the wrong
UVB bulb it literally causes medical problems in every part of their being. Also unfortunate is the fact that out of the million different UVB bulbs out there, even the ones labeled okay for bearded dragons, only a handful (literally, like 4-5 UVB bulbs) are appropriate for bearded dragons. The Reptisun 10.0 tube is absolutely the best
UVB light for Beardies available. An 18" Reptisun 10.0 T8 tube costs $37.99 at Petco (just the bulb, not the fixture, however Walmart sells an 18" T8 fixture for $10 and a 24" T8 fixture for $11, I own both). I don't suggest buying the Reptisun in a Petco or PetSmart store, but rather go to
http://www.petmountain.com where an 18" Reptisun 10.0 T8 UVB tube costs $23.99, and a 24" is $25.99. Then buy whichever fixture at Walmart (if you decide on a 24" bulb buy the 24" blacklight fixture/bulb combo that Walmart sells for $11, if you buy the 18" bulb they don't sell an 18" flourescent tube fixture for $10) and also buy some 3M command hooks and mount the fixture INSIDE the back top of the enclosure, centered. This way you're not spending a small fortune buying a new hood (I'm not sure how your enclosure is but you cannot have glass, mesh screen, or anything else between the
UVB bulb and your beardie, you will lose up to 50%+ of the
UVB light to the glass or mesh) and the new bulb.
What are you using to try and get the brown junk off of his nostrils? Is it just stained or is there actually gunk stuck to his snout? I can't tell from the photo, but if it's stained it might just need to wear off, if it's actually gunk stuck to his snout you need to get it off, but you don't want to rip skin off with it. And for future reference, never ever ever use any of those damn loose substrates for Beardies, and spread the word!!! You should never put a baby, juvenile, or even sub-adult beardie on a loose substrate of any kind, and as far as adult Beardies, the only even partially safe loose substrate is SCREEN-WASHED PLAYSAND, the plain old tan playsand you can buy at Home Depot for $3.50 and get a 50 pound bag of. And you still have to rewash and screen filter the playsand before you put it in their enclosures. I had my male adult on playsand starting when he was around a year and a half old, and he was on it until he was 11 years old and he died of natural causes. But it was a royal pain in the *****! I never fed him anything inside of his enclosure, he had a separate feeding tank that had it's own duplicate UVB and basking light setup because sometimes he would take forever to eat his greens or his crickets/silkworms. And I had to scoop off the top 1/2 inch of sand once a week, at least, and replace it, and if it ever got really wet or anything it all had to go because the risk of fungal and bacterial infections is too great. So no more sand for me. And I can't tell you how many bearded dragons have died as a result of their enclosures having either crushed walnut shells, crushed chestnut shells, or reptibark or just regular bark, or any of the brands of Calcium sand (should be illegal, it's made to taste and smell good to them so they eat it and get their Calcium, but when it gets wet it turns to a clump of basically a clay-like substance that sits in their gastrointestinal tract and just clogs it, and won't move). The walnut shells and chestnut shells not only are a breeding ground for fungal and bacterial infections and keep the humidity in the enclosure way too high for a bearded dragon, but when it's eaten by them it never breaks down, it either just sits in their stomach or intestines and doesn't move, causing a fatal blockage, or if it does move even a little the jagged edges of the shells rip their insides apart.
As far as the superworms go you'll get varying answers. I'm assuming your beardie is at least 16 inches long from snout to the tip of his tail, he needs to be to safely eat superworms, but if he's 7 years old I would assume he is at least that long. As far as how many to feed him in one feeding, I wouldn't feed him as many as he will eat, because they should never be lone staple protein. They have very hard exoskeletons and regularly cause impactions. My girl now is only 7 months old but is nearly 18" long, so she gets a couple small superworms as treats but never more than 2 or 3 large ones at one time. She would sit and eat the entire container if I let her, but I just don't trust them enough to feed them to her except for a treat now and then. Her staple insects are Dubias, crickets, and Phoenix/Calciworms/Reptiworms when I can find them (I'm probably going to start ordering either Phoenix worms or silkworms/silkworm eggs online as her main feeders soon, they're the best feeders in my opinion, loaded with calcium, protein, and vitamins and minerals, and soft so they never cause any impaction worries). Hopefully someone else who feeds superworms as a staple insect can chime in and give you appropriate information.