Describe where you are in the process. Cycled yet? How long ago didja finish if so? What critters are in there? What are you water readings? How long are you lighting too?
On #1 - New tanks experience diatom growth in the very early stages. Look that up and see if it looks familiar.
On #2 - again, where are you in the cycle? If finished, a clean up crew is needed and most likely a decent water change and sucking some of that loose dead matter off the rocks and sand bed.
I like to medium brush to get a lot of loose already dead matter off of uncured rock when cycling with it. Often, there's still enuf dying matter left after scrubbing to cycle anyway. And it gets you off the more serious clean up - where it sounds like you might be now.
"Life may not be the party we hoped for but while we are here we might as well dance!"