Where can I buy silica (blasting) sand for my aquarium substrate?

Instead of silica sand (which will encourage diatom growth and is VERY light, and easily moved by fish and picked up by filters), you might prefer diatomaceous earth (pool filter sand). It has very similar colors, and (if you are planting your tank) provides nutrients vital for plant growth (but not algae growth). It is also a bit heavier, so it will not be constantly flicked into suspension by fish, making it a threat to your filter's impeller. This sand is still extremely cheap; 50 pounds will cost you $10 or less... Feel free to email me if you have any questions. Soop Nazi EDIT: Thanks Tiki. Most of the pool sand I'm using right now is pretty light (standard) but there is also sand composed mainly of zeolite that is a gray/green color which I use a bit of (it is higher in nutrients for plants). A mixture makes a really nice affect, especially if you have any darkly colored fish which contrast nicely with the sand.  more