I tried that but with a 40 Quart Terra & my experiment went really really bad. I didn't really change the water, so the peat&spag got REALLY, REALLY, I WANT TO DIE RIGHT NOW, smelly. So I don't really have tips other than don't let anything rot?
My original Idea was to keep a mosquito pool on one end & my tropicals on the other end, it went so bad, the terra cracked.. probably from the smell. Haha, no. I slammed it on something..