Help? ideas for a paludarium

Depending on exactly how humid you would like the tank, it could be next to impossible to achieve your desired level of humidity with a screen top. Ambient humidity will also play a factor, where abouts are you located?

ANyway, keep us posted how it goes
 
What I would do is make a box of acrylic or glass, then put a screen top on it or a half screen half glass. Unless you have a fogger in the tank, it would be very hard to keep the desired humidity in your tank.
 
i was planning on putting a fogger in the tank, the half glass half screen sounds like a good idea but sounds like it would be hard to assemble
 
Here's an idea- check Craigslist, Freecycle, yard sales, etc. for a cheap 75 gallon (or other tank with same footprint), maybe one with a cracked bottom. Remove the bottom glass and stack it on your existing tank. Then just put a glass canopy on one side and a secure screen top on the other and you're set!
 
AquariaCentral.com