Hi Curt,

Welcome to the community. I am not sure what you mean by a stream, but really they can be as far apart as your pump can pump the water back to the grow beds. The problem becomes the cost of the pump you need to pump the water back, but if the head height is not that much of a difference, then the cost of the pump might not be that bad. Do you have an examples of what you are thinking of building?

Jason