Bob was most likely banned for giving Ill advice and defending the idea of overcrowded tanks repeatedly. I do not know for sure and don't even care why he was banned. But I do know that many people had to work really hard to undo the damage Bob tried to do here, and his actions since being banned are both juvenile and unnecessary. He could easily have found a way around the ban, returned and been beneficial, but he did not. he found away around the ban and started the same crap that caused him to get banned before. To defend grossly overcrowded tanks, Rumors and myths, offer poor advice , and then try to claim that he is doing a good job of caring for fish is kind of like shooting yourself in the foot to get rid of a wart. I would gladly have Bob here (not that my opinion really matters) if he would not cause a lot of trouble and contribute to the betterment of this hobby somehow. There are many things done by many people that do not fall under the category of "A good idea" but they are not offered as advice to beginners and are not defended when questioned. There is a far cry of difference between having an overcrowded tank, and defending it as an acceptable practice. Bob had been a huge disruption and a pain to a lot of people, and when he was cautioned by many he became a bigger pain instead of being sensible about what anyone had to say. As said earlier, I'll be the first to welcome him back if he wants to contribute something positive, we see our share of trolls here, and they become easy to spot after a while. We are all here to learn, and Bob could learn a lot without creating strife and confusing people who genuinely want to gain knowledge.
It really does take a lot to get banned, It's not something that most of us like to see happen, but when someone causes enough trouble, it does happen.
Just my two cents (which will by nothing in today's world)
Dave