[smokinreefer]

Well, that's a creative solution to keeping those guys isolated!
I'd imagine they'll look pretty cool once grown in.
Hard to say who out-competes who.
The GSP can overrun the Xenia, but the Xenia can grow atop the GSP!

And I saw of pic of your setup, lots of height to accommodate those powerheads. I think they'd be fine on opposite ends.
Alternating setting to create wave action or even just random setting would work great.