Bidirectional tidal flow

[Delphinus]

Not sure about the OM's but as long as you could have the motor turn very very slowly I suppose it could work. I wonder if it would just be easier to use some Tunzes or Vortechs and work with the controlling options to alternate gyres on a 6 hour cycle. Or just two separate closed loops with different inputs/outputs on each end. Actually considering the recent advent of controllable pumps (Red Dragon? I think? I dunno I'll have to dig up the reefbuilders/reeftools/where-ever-I-read-it link if you need more info), I think this last option could have the most merit because instead of having the the pump "off" on the slack part of the cycle, it could just be at 10% and thus avoiding stagnant buildup or critters seeking haven near the inactive bulkheads and so on.