Episode 9 of Season 1 is a stream that picks up on Cycle 30, right where the Water Purifier started working, with eleven duplicants and an alert reading Insufficient oxygen generation. This video goes after the carbon dioxide: a gas pump and a filter send it into a small sealed room, the closet of the title, where an Air Scrubber cleans it out. Along the way a liquid filter refuses to behave, stress climbs, and Sanitation research gets going. It ends on Cycle 33 with the scrubber running and the air across the base still poor.
A room for the gas
The Air Scrubber is in the Oxygen menu now. The plan, on the recording: it "needs to take in water and carbon dioxide which we're gonna pump up," and puts out polluted water.
A gas pipe leaves the pump for a Gas Filter, and Carbon Dioxide is picked from its list. Everything else goes out a second pipe to a Gas Vent, "and we'll just dump it back up."
Then a surprise: "this thing doesn't take in an air vent, it just takes in water." So the scrubber gets its own room, sealed with Manual Airlocks. "This room is going to be just a bunch of polluted air, a bunch of carbon dioxide pumping into the room."
Dirty water underneath
An alert reads Made a mess, and one duplicant seems stuck even though "there's a whole path right here." Down by the food there is polluted water: "That's not good." A Liquid Filter set to Polluted Water goes in with liquid pipe bridges, so the dirty water goes one way and the clean water goes up. At first the water shoots back and forth, until "now it's starting to go through."
It does not last. On the liquid overlay the filter is sending regular water out the side meant for polluted water: "why is it putting out regular water to the right?" It comes out and goes back in the other way. Later a stray pipe turns up under it, so it is rebuilt again, and its priority goes up.
Scrubbing, and stress
On Cycle 32 the room starts working. The scrubber's card reads Consuming Carbon Dioxide 300 g/s and Emitting Polluted Water 1000 g/s. "It takes in clean water, scrubs out CO2, puts it in the water."
Stress keeps climbing. "I think their stress is stressing me out." Now that water can be cleaned, "let's research showers and stuff," and the Research Station reads Currently Researching Sanitation. A room that is "not very decorated" gets Blank Canvases.
Short of air
"Wow, everybody's super stressed out." Then: "nobody's dying right? I think we're doing okay. Oh, we're not doing okay." The oxygen overlay shows most of the base in red.
The answer is more algae. A patch is marked for digging, "let's make it priority eight," while the duplicants sleep and the game fast-forwards. Research Complete (11) shows in the alerts: "we've also finished our showers and stuff." A Hand Sanitizer appears in the Medicine menu.
Where it ends
The scrubbing "is helping," and the purifier stays busy. The Refinement menu has a Fertilizer Maker that uses polluted water, so one goes in, with a pipe bridged over to it and power run in. Last comes a room with polluted dirt waiting to be swept. "This room is really nasty," with not enough space to build purifiers in it, and the video ends there on Cycle 33.