Living in Brooklyn, I can't find any pool filter sand, quartz sand, sharp sand, silica sand, or whatever you want to label it as! Very annoying. Most sands I can find at garden centers are too laden with salts and/or carbonate minerals to be good for use with CPs (I learned the hard way!) But I have had good success with freshwater aquarium sand. It's a bit expensive but it's nice and coarse, it's neutral, and it's available at every pet shop.
After searching all season, I FINALLY found some sand... Look in your phonebook for any sort of gravel/sand/rock supply places.. I found one here finally, lucked out at the local plant shop and a guy pointed me the right way. The stuff I got is 8 grit coarse industrial quartz, and was in a 100lb bag... But yeah, it needs to be silica or quartz.. You will also need to rinse it to get any salts/dirt/etc off from processing. http://www.growsundews.com/rinsing_peat_and_sand_for_carnivorous_plants.html This stuff, once rinsed, was nice and pretty and clear, like quartz crystal(go figure. lol)
WOW that is what I'm looking for. Mesh 8 .. amazing! Do yo by any chance remember the name of the place you got this treasure from?
I got it a local sand/gravel/rock quarry type place... The brand/company is Unimin, which is a world wide distributor.. You'll have to call around to masonry places or something like that.. Its "industrial quartz".