Display Refugium - Need Stocking / Setup Advice

[ZsWithTheFishes]

Hi All.

I will be setting up a display refugium off of a new tank - tank will be a 220 bare bottom into a sump. The refugium (24g/18in cube) is external to the sump and will be fed by a separate pump in the last chamber of the sump. It has an overflow that will return back to the first chamber of the sump. So far I plan on keeping macroalgae and a light stock, but I'm unsure on what to put in there and I need ideas.

- what type of flow would be appropriate? The overflow on the fuge can handle 700 gph. I did not want the refugium to have the full flow of the 220 main, but I don't know what turn over I should be aiming for. I assume I will need a powerhead in there as well.

- what are people's thoughts on sand beds? I've heard dsb won't really get me anything in a small fuge. I assume I'll need something for the macros unless they are all rock-clinging, and having some sort of sand bed would allow me some critters that I can't have in the main.

- any suggestions for macros or stocking? My initial thoughts were shrimp, but I'm running into a lot of reefer's block coming up with a stocking list and I am not experienced with macros.

- suggestions on lighting and a powerhead are always welcome.

I will post a picture of the setup when I can get to it.

 

[ZsWithTheFishes]

Picture of the setup:

 

[BitFix]

From what I've read, you don't want anything in the refugium apart from Copepods, amphipods and chaeto, because it may eat the beneficial microfauna; if you really want something I think a crustacean would look cool like a spider crab.
Normally flow is very low, so the algae can have as much contact area with the water as possible.
As far as deep sand bed goes, they house lots of microfauna and may reduce nitrates, also chaeto (the most common algae in refugiums) doesn't need any substrate, I would personally only add rock rubble, but a DSB also works.
I would add Chaetomorpha and microfauna, that's it. Chaeto doesn't go sexual like caleurpa and houses more microfauna.
Some people grow chaeto with expensive and others with super cheap lights, just look at your budget and look for either refugiums lights or normal LED lights.