IMO, "live" sand in a bag is a crock. Most of what was live when it was bagged isn't anymore. Worst case, there is decaying matter in there and will indeed kick of a mini cycle. Best case is, the
ammonia generated when most of the stuff in the sand died was converted to
nitrite and
nitrate by whatever bacteria is left, so you either get a dose of
nitrate, or sand that is no better than bagged dry sand.
I'd just add plain old "dead" dry sand. Cheaper and safer.
