I now have a home bioreactor.
This is what it looks like 48 hours after startup:
Of course, I only realized after the bugs started farting all that CO2 that I didn't actually have a microscope at home to see what they were doing and what was there. I may have to start a second bioreactor after finding myself a microscope capable of seeing who's at home in that jar, to see how the population changes over time.
Hmm, it looks like telescope stores often sell microscopes as well. Magnifying optics are magnifying optics, I guess!