Yet another sand question

[yosemite sam]

I have been looking high and low for Southdown/Old castle play sand to set up my 125 gallon again and have found nothing. I did however find Old Castle PAVING sand at Lowes. It says it's silica, and seems to be white and have small grains (the bag is clear), but i'm wondering what the difference is between play sand and paving sand.

 

[gregzbobo]

The southdown/old castle sand is very fine calcareous argonite sand. The paving sand you mention is silica, the main ingredient in glass.