Jelly's don't do well in rectangular tanks due to the flow patterns. If they get caught in a corner they almost always will die or become damaged. The flow must be in a circular motion, like the flow a gyre pump puts out. Also, they all require cold water, so you'd need to run a chiller constantly and have the tank in an air conditioned room. Anyone can put a beautiful piece of coral in any tank system and claim that you can keep it alive in those conditions, the real question is for how long? And will it really thrive?