This new 125 gallon project has been completed for a little under a month now. I wanted to wait untill the system become sort of established before I posted this topic. Two of my biggest challenges have been rectified with this project. They are controlling high Nitrates/ Phospates and creating a strong flowing river like environment for my loaches.
First part, reducing nitrates: My old tank averaged an 80-90ppm nitrate level with 1/3 weekly water changes. After 3 weeks without any water changes my new tank was at 40ppm Nitrates. I transfered all the water, the filters, everything, directly to this new tank. This system holds about 30% more water so I had to add tap water to fill the tank completely. It is too early to tell the long term results of the nitrate levels but for now, the plants are growing rapidly on the available nitrates. I started out with just one small peace lilly and now I have quite a few and they are all flowering nicely. I planted some beans and peas just for fun and they took off within a couple days. I rooted out an old stub from my yard and it has sprouted quite a few leaves (did not expec that) and seems to be doing well.
All plants are set in baskets that are filled with something called "earthstone", an inert material, just to hold moisture and keep the plants in place. The basket are set into holes drilled into a 4" PVC tube. One end of the PVC is the input where I use the water exited from my two canister filters. There is an auxillary pump on a timer that I use to flood the PVC at certain intervals. The 4" PVC tube then has a drain on the other end where airated mostly denitrated water drains back into the tank.
These plants only get nutrients from the tank so there are no added anything. As of now, the production of nitrates from the fish exceeds the plant usage and I would have to add more plants to balance this out. I imaging that with the addition of plants, I would have to add iron suppliments or trace minerals.
Part 2: I created a turbulent tunnel using a 950 GPH pump and a 4" acrylic tube. I have not done calculations or flow rate but at the moment the water through the tube is more than 950 GPH based on some fluid dynamics. There is a strong vacum on the input side of the tube where the pump enters and sometimes it sucks unsuspected fish in. This vacum is apparent in one of the pic with the little blue airstone outside the tube having its bubbles pulled sideways.
Also, the hose from the pump is angled in a way to get a spiral turbulent flow, like a tornado.
This pump is on a timer as well and like "moths to the flame" the loaches enter the tube when the pump comes on. Only the clown loaches enters and only one makes it to the far end by himself and sits there till the pump shuts off. The others have done but dont stay for long and usually by following him or clinging to each other. I have lots of VDO's to upload that I have taken of this. The photos dont do it justice.
Here are some pics I took with my phone and couple with camera
Weed Stub
Healthy looking plant flowering
Acrylic tube input end. only he alone can sit here without being twisted around by the get stream of the pump hose. The others swim up halfway but then backs down to the mouth where the water exits.
Here are some gravel in the flow
Tube exit:
Bubbels being sucked into the tube with the current generated by the flow velocity of the pump.
Apologize for any spelling errors, gramma errors or any missing details. Feel free to ask any questions
Vance
Excellent work. 
Excellent setup!! I love the concept and way you put it all together. This is very inspiring. Thanks for posting!