Is My Waterfall Killing My Frogs?

[Diver]

They need much better ventilation, a full screen top at least. Moist, stagnant air will indeed kill them. 60% humidity is great, (I don't know who would suggest 90%, that's complete nonsense unless you're trying to bred them in a rain chamber) but in reality none of the cheap hygrometers give you more than a vague clue anyway.
You don't want ANY condensation running down the glass.

[kletsgo]

Alright. With some wire, metal caging, fiberglass screen and plenty of tears and cursing, I have a really ugly but functional screen top. I'm really glad you suggested it because as I was taking down the original top, I noticed mold starting to grow in a couple of places. But, now the tank is mold free and almost condensation free! However, now the waterfall isn't working (I turned it off to mess with everything in the tank and now it isn't working at all) but I think I need to redo the whole "water feature" anyway because the side of the pool apparently isn't sealed all the way and the entirety of my substrate is waterlogged (if you push on it, a puddle forms around your hand). I'm thinking of just emptying the entire tank, draining the water, ringing out the substrate and just getting them a water dish rather than an entire "pond". *Sigh* I can't wait until I get the hang of these guys again, because right now every day brings up a new challenge.