this idea is awesome. I have a 135 display fuge that I just plumbed to my main DT, and I was trying to figure out a direction to go with it. I think this may be it!
I think that would look amazing, and would love to see some pictures if this is the route you decide to go. Depending on the macros you choose and your scape, it would look vast. Tons of tiny fish swimming through the roots system of mangroves would be amazing.