Drilling & Plumbing - basic question...

[greathouses]

I have lot of experience with saltwater tanks - reef and such so now that I am embarking on this Vivarium project, I am wondering why not drill and plumb a tank with a small overflow pipe/box that leads out of the bottom of the tank & into a bucket in the stand. Then have that bucket equipped with a pump to lead back up to the top back of the tank where the water feature / falls would start? It's my impression that it would make for a nice & easy water change and would keep the whole thing running cleanly. Am I dreaming over hear out of inexperience? A bit of background is that I am the mother of a 7 yr old who says he wants to be a herpetologist when he grows up. I also have an 11 yr old girl who is "going to be" an actress / dancer. So I figure in equal to all her dance lessons.$$$ he should get the frog tank that he has been asking for many moons. I myself am an animal lover... and help him to take care of his bearded dragon while he learns from my rabbit breeding. His dad has a cat... and we are all big lovers of all! So husbandry and research is nothing new to us. I just got a 40 gallon hex with stand/light $35 bucks on craigslist so I'm off to a good start. Now it's time to plan! Oh yeah he is coming back in August so I want it all to be a surprise. If you guys think I need to sketch my plan out for you I will but I thought that it made sense. Please any input would be great!