Although I haven't been fortunate enough to see Glenn's tank in person (although I'd love to), there appears to be two common themes in his approach: happy/fat fish and ozone. One could assume ozone coincidental but given his self-proclaimed QT process or lack thereof it appears ozone is his insurance policy when his fish aren't happy. Personally, I find it hard to believe tanks are truly disease free just like saying something is 100% pure for very long. Keeping things in check appears more likely. The caution I have is recommending what other people are saying is very risky. If ozone was the key to success, it would be a ubiquitous piece of equipment in all aquariums like a heater or lights. I can have the same equipment and do everything Tim or Mark or <insert pro reefkeeper name> does and still not have an uber cool reef. Similarly, because I have ozone will I have Glenn's success with fish? Maybe more likely than without. I suspect those disagreeing with Glenn's approach are more unhappy with a lack of QT as that might lead a newcomer astray.
