I will come up and help you build it if you want Christy. It looks easy.
1) Looks like a dust bunny.
2) I'm not sure it does anything. It just looks like a threaded cap on there. My guess is you could tap into that and put a small John Guest valve for testing reactor pH.
3) Water IN
I know I'm new at this stuff too but I think I could help explain how these things work. Come for a visit!
If I'm wrong oh well but these are my best guesses.
