If I had the room and the cash, I would convert my present mish-mash of tanks to a rack system where water changes would be easier and tank sizes would be more uniform. Right now I use stands that let me put an upper and a lower tank on each one but unlimited space would mean everything could be at eye level instead. A central filtration system for each kind of water would also be a big plus since it would mean less upkeep for me in terms of cleaning filters. I already have almost as many tanks as I could reasonably care for without making it a job but better systems like automatic water changing and central filtration might tempt me to get a few more so that I could expand my species selection to more endangered species. I already breed several.