Sorry but No3 (nitrates) do not evaporate nor does carbon break No2(nitrite) into No3.
X2
Sorry but No3 (nitrates) do not evaporate nor does carbon break No2(nitrite) into No3.
I don't have any personal experience with saltwater tanks, but my understanding (through knowledge gained from here) is that liverock and protein skimmers are what keep nitrates down in saltwater tanks. There is little anaerobic bacteria in freshwater tanks, and I'm pretty sure the anaerobic bacteria in live rock are what keep nitrates low, and protein skimmers remove the waste from that metabolism. I could be wrong about that, but in freshwater tanks you have to keep up with water changes more dilligently.
and, in the long run, a peacock bass and two aros are gonna need more than 220 gallons.