There are other things to consider than just bacteria. If people get smart and cycle with diverse microfauna, then the sponges, worms, pods, stars, etc. all will want reef quality water. Of course Dr. Tim's main concern is about bacteria, but that is just one small piece of the picture for a diverse and thriving reef tank. Some people still want to use products like grunge, IPSF, etc. to cycle a tank in addition to bacteria... so if you are one of those, then best to ignore Dr Tim on this one.
Amazon has IO for $40 a box right now, if you all want to do a "group buy" that way... bags are a dollar cheaper.