Bidirectional tidal flow

[sphelps]

Pretty common setup, it's typically done with two separate closed loop systems. One CL system with the output on one side of the tank and the input on the opposite side. The second CL system is the exact opposite. Put them on separate timers and set them however you want. You could do it with a single system and pump but you'd have to use special solenoid valves which will cost more than the additional pump and plumbing. The OM won't give you exactly what you're looking for.