FWIW, I am still going to use GFO, the high capacity stuff from bulkreefsupply. I just started this thread to find out if there was any more real information about AO and how it really compared to GFO. Since there still isn't any new information like I hoped, and also after 48 hours of using AO my phosphates are only dropping .01 per day (.09 starting, .08 after 24 hours, .07 after 48 hours) I think I like the effectiveness of GFO over AO in how quickly it works. GFO just doesn't seem to last as long.