I have a 14' x 14' x 12'' sandbox in my backyard...literally...lol
I have no shortage of asnd for my aquariums...lol, so naturally, I've used play sand before.
I've had it in a 10 gallon with no problems, and I currently have it in my 20 long with my N. multifasciatus. I've never had issues with it, but make sure you rinse it really well. It takes forever to rinse, and you'll lose about half of what you started with, but in the end, it's defaintly worth it.
65 gallon low tech planted