You can also see this happen on a smaller scale with your mop, if you clean different liquids in one go, sometimes you’ll see/hear the excess liquid spill from your mop into the tile below your character, as a chemical reaction created matter out of nothing (?) and your mop exceeded its capacity (100u).
I’m actually not sure what reacts with what, but I see this happen the most with blood, followed by slime.
I haven’t found a sweet-spot for how much to fill a trolley (800u maximum) yet, but 2 buckets of water (500u total) works well, and you can just carry some more in a bucket in your inventory.
this matter out of nothing is more common if you have played chemist before; off the top of my head mixing 1u of plasma with oxygen (to make Dexalin) will create more units of liquid than the amount of oxygen you put in. I’m not a chemist IRL so I don’t know if this makes sense or not lol, or is if just a representation of some other reaction that would be too much trouble (and not worth it) to code, e.g: it’s foaming or something that would make the liquid take more space on the beaker without actually creating more matter.