I decided that's too much sand. 3" is ridiculous. Scratch that.
Incidentally, someone at another forum said that silica sand is best for Cories because it is more round. That it can be found in play sand. I looked at play sand at Home Depot today and I could not fine anything that specifically said it contained silica on the bag. But then again maybe bags don't always say that. It just sat there and didn't say anything. Stupid bag.
Also, in Googling silica, I read that it's linked to cancer. So I dunno.
~Behold the Savior of mankind,
nailed to the shameful tree.
How vast the love that Him inclined,
to bleed and die for thee.~