20 long refugium

So - I'm going to set up a 20 long as a refugium. I have absolutely no room left under my 75 for any additional equipment, and I'm trying to figure out the best way to set this up. I'm hoping to set it up as a display, with 2 10k or 6500k T5 lights.

What would be the best way to plumb this into my existing sump? The tank would be sitting on a stand next to the 75. Ideally, I'd like to have it set up with some live rock, perhaps house a small mantis in there as well, if possible.

What would be a list of safe macro algaes to put in there (aside from chaeto), that would not only keep the nitrates down, but would also look nice and not go sexual? Should I use mud with sand on top for substrate?

 

A 20 long displayed is exactly what I have for my fuge.
Easiest way to do it, would be to set it up so it is higher than the sump. Drill both sides of the fuge. T off of your overflow, and have that going into one side, then just have the other side gravity feed into sump. I put a albow fitting on the sumps drain on the inside to raise the water level.
As for macros, right now I have chaeto, ulva, shaving brush, mermaids fan and halimedia. Stuff like fire fern, codium, flame algae, gracilaria would all make nice macro's. Ulva and gracilaria trimmings can also be fed as veggies in the main tank. Or you yourself can eat the ulva (common ingredient in seaweed salad). Mine is lit by a 65W PC fixture. Does a good job at 10K, but I am thinking of switching to 6500K.
Here's a pic of mine:

 

That's a nice looking fuge there.

I would do a T off my drain, but that would require the top of the fuge to be lower than the base of the display - which would make it very low to the ground. I would also have to have the same side drilled - because the drain on my 75 is on the left side, and the only way I could have it gravity fill the fuge is to have the fuge very low to the floor, and drain into the right side of the fuge. The sump is also to the right, and I would have to have it drain to the right into the sump. Hence my dillema.

Good list of algaes - I'm getting a list together for reefcleaners

 

So I think I'm going to pump water from my sump into the fuge using a low gph pump, and have it drain back into the return pump side of my sump. Think that will work? Maybe 300gph?

 

What do you need the fuge for? Nitrate reduction? To increase pods?

 

and I would go with mangroves...pretty much awesome

 

Both.

Mangroves are on my list in addition to the macro algae.