Croyf

Hi all i currently keep a bearded dragon and would like to start keeping dart frogs. I have a question tho as i have never kept them b4. When setting up the vivvarium can i use like egg crate with plastic pipe holding the eggcrate up, put screen on eggcrate then substrate on the screen. and have the tank filled with water under the egg crate level. so i can put a submersible pump in the water under teh eggcrate to take water from the bottom off tank to pump out the top to make a waterfall or is it a bad idea having the bottom of tank full off water. Just so i can set up my tank and let it grow for couple months b4 i purchase any dart frogs thanx for taking time to read this and for any help.