I have been doing a little searching and came across these 2 sites.

http://www.yardright.com/sand.htm

http://crabstreetjournal.com/product.../playsand.html

Now Im confused :? , If this sand (above) has silica in it ... and you purchase this sand for your kids their health is at risk? Now it would seem that there would be some huge law suit somewhere if this is true.

Also if silica is an ingredient in making glass doesnt that make a glass tank useless or is it that it cant leach from the glass?

Another .... http://safesand.com/information.htm