Sounds exciting! I'm setting up my tank for my tree frogs, with a pool.

What I'm doing is I have a very small under water filter that I picked up for $15 at PetSmart that circulates the water, up to 5 gallons, and it's adjustable. I am using river rocks for the bottom and will be using it to build up a land mass for about half the aquarium. I've also ordered live Sphagnum moss for the entire land/water edge. It has an antiseptic quality that makes it perfect for frogs. I found it cheap on eBay, and people will sometimes give discounts to froggers. I even found someone offering a frog assortment package of 3 different types of Sphagnum moss specifically for frog vivariums. Other than that, I'm using philodendrons submerged and above water, and some aquatic plants typically found in the lakes around here, though I got them from a pet store.

I would like to find some ferns that I could plant in there that won't get root rot from the water base, tree frogs need lots of places to hide...

Anyway, good luck! Sounds like fun.