I mostly use a spray bar in my aquariums. I think for the reason most people use it, distribution of nutrients, even water flow, and simply because it comes with our filter (mostly like Eheim or Rena Filstar). To my knowledge, the ADA standard is not to use a spray bar. Instead a straight "jet" or gushing water flow from the output is recommended, and their outflow products reflect that. With Amano being so successful in growing aquatic plants he must be onto something right, but what? Why doesn't he use a spray bar? -John N.