I figured that this would be a great idea since I have growing fish! I bought pothos, but my tank setup isn't that great for placing them in the top. I have a tight hood, so there's barely any room for them. I have a sump underneath, but it's crowded and I don't really want a light in there. I'm building an auxilliary tank for growing them. I bought an acrilyc vase, a small 180 gph pump, some tubing, bulkheads, and some lava rocks. The water fro my sump will be pumped into the bottom of the vase, up through the lava rocks, and out an overflow back to the sump.
Here's where I'm at now:
The vase was drilled and bulkheads installed, offset on purpose.
View from the top with the overflow and the false bottom installed above the inlet, hoping to keep it clear and have a diverse path for the water to rise up.
Dry mock up, just waiting for the silicone to cure. You can see the tiny little pothos peeking out the back of my tank. There is a big set of windows that shine in from the left, lots of light.