Me and my girlfriend recently decided on getting her 8 year old daughter a bearded dragon for christmas. After spending some time researching I've decided on building my own terrarium mainly because I want a big one and costs to buy one brand new are to high. I've seen alot of great do it yourself videos and pics of vivariums on the Internet but I have a few questions for the one I am going to build. I've researched that a adult bearded dragon needs about 8 square feet of living space which equates to a 4x2x2 terrarium. I am going to buy my dragon from a local breeder who has them with the German giant gene making them somewhat larger then regular dragons. That and wanting my reptile to have more then just adaquate living space I decided I was going to build a 5x3x3 terrarium. Researching has also told me the the wider your terrarium is the harder it is to regulate heat. Would a 5x3x3 terrarium be ok to use or should I make it a 5x3x2 to maintain heat from lighting. Another question that retains to this is in researching I've been leaning on using a mercury vapor basking light as it is said it produces more heat, has a longer life span, produces more uva, uvb rays and leads to a healthier pet. Is this true and is it a good choice for my larger terrarium? Last thing I'd like to ask about is the top of my soon to be built terrarium. I've read that you want proper ventilation to let moisture escape to keep the humidity down for your bearded dragon. I also know that to much ventilation can make it hard for you to keep temperatures up. I wanted to build a screen top with wooden framing across the whole top that can open up or slide open on half the top of the tank for easy access from the top if needed. So my last question is... with the top of the terrarium being open with the screen is that too much or not enough ventilation? Should I just make a solid wood top and cut holes for the vents and lights? Looking to get started on this project as soon as next week so any help greatly appreciated!