Greg I tumbled through Biopellets and took a hard fall and I prefer the more natural approach of a refugium, the Arid just fits my space restraints better than a large refugium. If I had the room I would have a 100 gallon refugium instead of the Arid as it is a pain to clean. I understand the idea of a bacteria driven system, but do not understand the control and worry that you can feed the bad bacteria as well as the good. Lighting and the shift toward LED also plays a big part in how a reef is run because you used to be able to get away with less nutrients because of the quality of light, with spectrum questions and uncertainty of LED lights the nutrients in the water play a much more important role.
Balance is key and It has taken me many years to get a grasp of how Nitrates, P04, and Carbon have to be balanced to all stay stable and this balance is as Important as Alk, CA, and Salinity.