I personally used Quickrete medium grit (30 grit) sand. I did play sand in my girlfriend's tank. (all we could find at the time) I can't say that there is a huge difference between the two, aside from the fact that mine required a little less rinsing, and settles easier when my fish kick it up. I love the look of sand. I've got pics of my setup in this thread. http://www.aquariacentral.com/forums/showthread.php?t=133162 Recent pictures are on page 4.