I want to make a pool in my dragons tank to help keep the humidity up, but dont know how to go about sealing the water in one area. What should I do?

Well, you can use a piece of plexi glass cut to size and some aquarium sealant, and then add a filter.

But since you should really be concentrating on a new permanent home, I would suggest a large plastic tub, almost like a cat litter pan or wash tub. Then you can remove and dump as needed.

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My name is Liz
Do what's best for the animal, not what's best for you.

Yea, I'm working on a new home too, but since the humidity drops to around 40 I get concerned. And speaking of a new home... are these any good? Reptarium.com

Not really for your usage. Unless you wish to heat and humidify the whole room.
They are a mesh sided enclosure which is great for airflow but horrid for trying to maintain a given temperature and humidity. Even the largest of them is still a bit small for a WD. However you could use it as a starting point and encase the thing in plastic sheeting (shower curtains, plastic drop cloths, etc to help maintain the environmental conditions. Even so you could build basically the same thing from PVC plumbing pipe at a fraction of the cost!
What I think is strange is they show in the pictures the lamps sitting directly on top of the mesh.
A hot light bulb would quickly melt a hole in the mesh!

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Merlin,
What's Life Without A Little Magic!

I tried to use them they suck. Have you tried using fine misters in your cage. I have used them with great results Mysting king can help if you dont want to make your own. I do know dragons like water. And you are talking about water dragons right just to make sure.