Sand questions

If you're doing freshwater, you don't necessarily want your substrate to be that deep. You really just want enough to cover the bottom. If I were you, I'd start off with a 50 pound bag. That was more than enough for my 6'x18" tank, and I ended up throwing some away.

You can paint with Krylon Fusion if you'd like.

If it's a glass tank, I'd remove what he did with a razor blade (brand new nice and sharp one). Just wet the surface and have at it. Razor blades won't scrape glass if you do it right.

Then paint the outside. It'll look a LOT better. This is what most people do.

50-75 lbs of sand covers a 6' x 18" with room to spare, so you might be able to use 75-100 lbs for a slightly wider tank.

This is what I've read.

http://www.oscarfish.com/article-home/water/72-heterotrophic-bacteria.html

It suggests that at 2-4" depth there will be anaerobic activity with no hydrogen sulfide. (Basically, denitrification.) It's below 4" where there is an issue.

Any updates to this theory or is 1-2" just being conservative?

Moved to setup and filtration