Take a look at this page
for a visual difference between a couple types of sand.
Your average "Play sand" is silica sand, typicaly has sharp edges (as shown in the page above) but will NOT release silicates into the water. That is a common misconception.
If you can find an argonite based play sand (such as oldcastle, yard-right etc) then the grains sizes have much more variation, rounded edges which allows it to harbor more sensative substrate fauna, and also helps maintain the Ph balance in your system. Argoniate has nothing but positives, silica sand simply has fewer positives (a couple argualbe negatives)
if you find the right argonite playsand at the homedepot, I got 4, 50 pounds bags for around $5 each.
It's worth the effort to look for, don't you think?