Different way of using Pothos plant for Nitrate removal. Help needed...

[Myarbro]

with that design you need a small pump.

if you put gravel on that refugium you will slow the water flow.

In my refugium I have a little more than one inch of water in the water inflow and the depth then decreases gradually in the way to the water exit, wher it is real shallow.

Don't forget that the Pothos will benefit from light.

They get plenty of light.

How about taking a long but thin PVC, running supported through the middle of the tray all the way to the end. Drill holes on either side and bottom. Plant the clippings and media around it. That way, I could use a stronger pump for more water flow, and it could distribute water evenly.

Or I could just decrease the diameter of the return hole, allowing some water build up in the tray?

 

[Miguel]

Or I could just decrease the diameter of the return hole, allowing some water build up in the tray?

this

 

[Nomonsta]

One solution to how big to make the outflow holes is to make the outflow an overflow where it spills over at the height that you want to keep the waterline at, and make the spill way big enough to handle any volumn of water. That way the pump can't overrun the outflow, and the water level wouldn't go lower than you want, even if the pump stopped. To keep water from flowing back through the inlet when the pump went out, the inlet would need to be at the desired water level also.

 

[Nomonsta]

After looking at your drawing again, you can simply put a divider in the tray right before the down pipe that goes from the bottom of the tray to the level you want the water. Then the water will build up behind the divider to the desired water level, spill over the divider, then down through the bottom drain just past the divider.
Make the drain as big as you want to handle a lot of water, and that divider will regulate how much spills over into it.