15 gal nano, 20 gal refugium, your thoughts...

NO that wasn't a typo, lol. I have an established 15 gal nano, and a spare 20L tank that I don't care to dump C-notes to fill with live rock, so I'm gonna make it a fuge. It's going to be even-level with the nano, and I'll put the DIY skimmer and kalk doser in/over the fuge.

I want to grow planktonic food for the fish (one small damsel, ocellaris, and goby) and for the corals (xenia, star polyp, shrooms, one small BTA). I live on the coast of SC and local mud/sand is perfectly legal to collect (at least in a 5 gallon bucket), and I already have the 20 set up and curing the sand/mud (also starving any parasites). The sand bed is only 2 inches deep b/c the sand is a fairly fine sand. I want to grow hair algae so thick it looks like a spinach factory exploded (for the copepods). Should I go with 6500K lighting? Seems like those new "screw in" CF bulbs that are self-ballasted will work well for a fuge. 20w 6500K bulbs are $5 at Wallyworld. I can't wait to see what grows in this thing!

What are the thoughts of the experienced reef and 'fugers out there? This is my first reef and first fuge (plenty of freshwater and plant experience) and have done well so far.

I won't be able to overflow the 20-fuge, but I'm not totally concerned with killing the microlife. I'll be using a fairly slow circulation (sub 100 gph) anyway.

I added some mud from a local inlet (I live near the coast) and cured it. Now I'm waiting to get the lighting installed. The silty mud is crawling with polychaete worms and the water is swarming with various copepods. I can't wait to get the fuge all lit and connected.