A system, method and structure are presented to allow water from a fish tank to be pumped upward to an aquaponic trough on the top floor in a multi-floor greenhouse structure, from which the water will have a gravity-fed and unpumped flow to lower troughs. Furthermore, the application describes a plumbing system to control the feed of pumped and gravity fed water through the various aquaponic troughs and back to the fish tank at predetermined intervals.