In many cases, volume is over rated; but good aquaristic practices are necessary to do the things you have mentioned. The smaller the environment, the quicker things can go wrong--but good aquaculture will belay some of that. Many east European/iron curtain countries often have done more, with less. Part of the issue was intensity, innovation, and good aquaristic talents. Though those are also found in our current hobby; perhaps not like in the early years of this century, but still good aquaristic practices are seen...and that's my plug nickel.