A study a few years back found that Southdown playground sand was then a better match of particle sizes for making a
Deep Sand Bed than commercial aquarium sands for the time period. Since then, the commercial aquarium sands have figured out sugar-sized sand pretty well. It was also under $5 for 50 lbs when commercial sands were 5-20 times that price. I've heard reports that it is more likely to contain nutrients like phosphates that can feed
algae blooms, but if you let you tank do a long (multiple months) cycle period after adding live rock & live sand, I doubt that would be a big problem unless you have fish or inverts that like to burrow. (I've read that the ideal scenario would really be to go close to a year after adding live rock before you add fish to have a really healthy ecosystem.)
Whether you want DSB, bare-bottom, or something else really depends on what you are trying to keep in the tank, from my reading, but never trust just one source, IMO. Plus, people tend to remember spectacular success or failure, but not remember all those steps in between. Also, a tank set up for one goal may end up being used for a different one.
