Hi Ken,
Looks fairly good to me, particle size might be a tiny bit to large for our warm summers (not this year though). Although the water retention seems to balance that our a bit. Please do what Repotter suggested.....soak it in warm water in a take away container and shake it every day for a week. Replace warm water daily and see what remains after a week. If its goop, i wouldn't use it, if theres clay-like residue, i wouldn't use it, if theres just some small amount of fines, i would use it (sifted).
Repotter, this product is not gravel. According to the internet site that sold Ken this stuff, its actually diatomite, a substance made from non crystalline
silica........gravel is usually a crystalline form, such as quartz. I found this information from the site Ken gave us
http://www.maidenwelldiatomiteaustr...nfo/default.htm
under the heading "chemical report"
JayC