my real bottleneck right now is sand. I don't ever have enough sand to supply all the filtration required to get rid of the polluted water and oxygen. The polluted water thing is really a detriment too, because I'm kind of reliant on a polluted water geyser for supplying my electrolyzer, so without the ability to turn it into fresh water the oxygen supply will come to a grinding halt.
I've been crushing rocks to get sand for the time being. It's not great.
Good news everyone! It's been a while since my last update, but in that time I've uncovered a cool steam vent, and more importantly, a polluted water geyser! it's still a MESS and plenty of the dupes keep coming down with slimelung, but for now, we have food and oxygen. Next thing we really need (besides sanitation) is a reliable source of power and loads of it. After that, steel and the midgame.