I don't think it's the tank itself, since it's just a glass tube that houses the cartomizer. Rather, I think it's the cartomizer that's making the noise.
When you say loud, what type of noise is it? Is it a gurgling sound? Is it the sound of hissing, and popping? If it's the latter, then that's just the cartomizer doing its thing.
I hate to be
that guy, and I'm guessing that Ben doesn't mind you asking here, but, your question(s) about general vaping may be better received, (and answered much quicker), if you posted them in the appropriate sub-forum. Not saying that I mind helping, because I certainly don't. But I opened this thread that 106 views, and I'm the first reply.
If you posted in General E-smoking, you'd get way more responses:
General E-Smoking Discussion