Laminar flow aquariums

[Bawb2u]

I built a setup years ago using two Sterilite containers on a planted 75G tank, drilled both tops and put two fittings one side of each box, plumbing two canister filter intakes to one box and two canister outputs to the other. On the intake side I filled the box with floss as a pre-filter. By putting them sideways on each end of the tank I got a strong one-way flow with an easy to clean pre-filter that had a strong current with minimal swirling and eddying currents. It made the plants move in a single direction just like in a river and while it took up more space than I liked it worked very well.
Here's an example made with my mad paint skillz.

 

[WalterMelon]

Whats the total flow rate with the two canisters in GPH?

 

[Bawb2u]

Whats the total flow rate with the two canisters in GPH?

I don't really know. The filters were both Fluval 404's but I'm sure that through mixing and turbulence in the "directional" box some flow was lost but as it was heavily planted and not overstocked, so I wasn't overly worried about a high volume turnover. Nitrates stayed low, no mulm built up on the bottom and the plants stayed rooted but bent and waved in a natural manner, so I considered it a sucessful design.