Yeah, 20 gal. is much too small for an adult dragon. And I would not breed her again, she will eventually become very stressed , especially since he's biting her neck pretty hard. She may retain sperm [ many beardies do ] and have another clutch . How many clutches has she laid and how many babies do you have right now ? The zilla bulb is not a good one IMO, if it's a t8 you're still better off getting the Reptisun and yes, mount it inside. Your temps. are too hot unless you put them out briefly using the kiddie pool in the morning when it's 70-80F at most and providing shade around it.