They supposedly bagged it in the same places in Florida where they bag the carib sea. ...only at like $2.79 a 50lb bag. It is super-fine too, which really helps with denitrification and phosphate exchange.
After they quit carrying it and the nationwide search started (what do you think, about 10 years ago?), there was a pallet and a half on close-out all of a sudden at Dome Depot out of nowhere. I ditched my wife and nearly ran up front to buy it ALL. There were reef clubs arranging 18 wheelers to haul pallets of it back from Hardware Stores in the south - I think that it was coming out to like $10 a bag, which is still a bargain.