YOur book was right Andy, collected sand should be treat like freshly collected live rock. I would definetely put any sand or rock you collect through a curing process before you add it to your tank. If its not aragonite, or is just lightly covered in aragontite, the sands buffering capability will be poor to non exisitant. Aragonite will disolve at a lower pH releasing Ca, strontium, bicarbonate, and a couple of other elements I think of. Aragonite is usually used in deep sand beds, plenums, and Ca reactors. Whether or not you use aragonite sand depends on what your looking to do with your tank, I would suggest it in any case but thats just my opinion. Go talk to Dr.Ron on --(reef central), he could give you the best info on sand and collection.HTH