The black one is 7g, manufactured by All-Glass. When I bought it, about a year ago, they were in most of the lfs. Shouldn't be too hard to find. Still see them around here.
Here's my webpage for the 7g:
http://www.lostmymarblz.com/7galreef.htm
For the 2.5g:
http://www.lostmymarblz.com/2-5galreef.htm