Possibly stupid technical questions:
1. I put the red cap the air lock came with back on the air lock. Is that a do or a don't?
2. Does the vodka in the air lock evaporate? It may be my imagination but it looks like there is less there than when I started, but that may be a function of the bubbling playing tricks with my eyes.
Yes put the red cap on and don't worry about the vodka. I've had some last for three weeks. You can always add a teensy bit more if needed. But don't add too much because it can get sucked back in. (Not a problem, it's just that you only need that barrier so volume isn't usually an issue.)