Episode 8 of Season 1 is a stream that opens on Cycle 26 with ten duplicants and carbon dioxide still hanging around the base. This video is about turning dirty water into clean water: a Bio Distiller goes in, a Water Purifier goes next to it, and the purifier refuses to run for most of the stream. Along the way an eleventh duplicant joins and Air Scrubbers become available. It ends on Cycle 30 with the pipes rebuilt and the purifier's water routed down into the reservoir.
A distiller and a purifier
The thing that would scrub out the carbon dioxide hasn't been researched yet, so the commentary turns to the Refinement menu. The Bio Distiller turns slime into algae, and it "emits bad water but no CO2." Right next to it goes the Water Purifier, which uses sand to clean polluted water and leaves polluted dirt behind.
The plan is simple: the distiller's dirty water pipes into the purifier, and the clean water comes back out. Later, showers and other buildings could feed it too. The algae has run out again, though, and the distiller needs slime, "which I didn't really factor in yet." A ladder goes up toward a slime patch, and the dig gets top priority.
Stress and decor
"Oh, we're really really stressed out." One duplicant is worse than the rest. A Mess Table goes in by the food, "a place to eat and de-stress," and the Decor menu now has a Sculpting Block and a Blank Canvas. The decor overlay shows plenty of bad spots, so canvases go up on the walls. A while later, "somebody painted. That's nice," and near the end the commentary does a double take: "Oh, it's a statue."
Frankie, and air scrubbers
On Cycle 27 the DNA Blueprint screen offers Nails, a Level 15 Runner, Frankie, a Level 7 Body Builder, and Hassan, a Level 9 Runner. Frankie can't build or cook, "which is fine," and is "decent at learning." Frankie joins as the eleventh duplicant and is set to combat tasks on the Jobs screen.
Then a research finishes, and the Air Scrubber shows up in the Oxygen menu. It filters carbon dioxide out of the air and puts out polluted water. The build tool comes out to place one near the top of the water line, with a gas pump below to push the gas up to it.
Not pumping
The purifier is built, but its card reads Not Pumping. It holds almost 200 kg of sand and a little polluted water. "I'm really confused. Why aren't you doing things?" Polluted water piles up instead.
Maybe the pipes are backwards. They come out, polluted water spills on the floor, and the mop tool follows: "Please don't do that, please stop." The pipes go back in the other way around. A pipe now holds 10 kg of polluted water, and the purifier still isn't pumping. Off to one side a Steam Geyser reads Rising pressure, and the commentary eyes it as a steady source of water, "I mean it's hot water."
Somewhere for the water to go
On a closer look the in and out markers were right all along. So the clean water stops going into the main pipe. A new pipe, with a bridge, runs from the purifier's output down into the water below, so it can "dump it down into a reservoir," and a floor goes in so it can be built.
On Cycle 30 it clicks: "It was working, I just didn't have anywhere for the water to actually go." Slime becomes algae, the polluted water becomes clean water, "there we go, awesome." The video ends with loose debris swept up at priority 6.