It's always a good idea to utilize gravity every chance you get when designing an aquaponic system. Place the pump at the lowest point in the system and pump the water to the highest. This design is no different. I have a submersible pump in the buried sump tank which pumps the water up to the highest point in the system, the fish tank. From there, via a solids lift outlet (SLO), the water overflows into the heavy solids filter. The water continues to gravity flow from the heavy solids filter into the two media beds. As each of the siphons are engaged, the water evacuates the media beds and drains into the deep water culture (DWC) beds. After the DWC beds, the water gravity feeds back to the sump and the cycle begins again. Utilizing gravity to move the water most of the way along its journey through the system is very energy efficient.