what's he eating, he does need fattening. Have you tried new life?
I do NLS flake, garlic infused pellets, sheets of green nori, and mysis shrimp. A good sized sheet gets put in every day, buy flake, pellet, and mysis are alternated between. The tang takes no interest in anything but the nori sheets. Im open to other suggestions though, as I like my fish fat, and he is the only one who isnt.
sump design looks good man, designing that stuff is fun isn't it?
a couple things.
1. think about using a filter sock to keep detritus out of the sump.
I dont like filter socks. I think they are a nitrate bomb and need more maintenance then I am willing to do. Sounds bad, but its true. I have a bunch of hermits running around in my sump to deal with the ditritus that settles.
2. you might need more room in the top of the sump for when you turn the pumps off (very, very important). What happens when you turn the pumps off is all the water in the pipes flows back into the sump, you really don't want that baby to overflow. Already calculated that, and I am well within the limits. I have less the 3 gallons spill over when the pumps are off.
also with the water height, 11 inches deep also might be above the optimum water level for your skimmer to work well. 6 - 8 inches is pretty common for smaller skimmers. Call the manufacturer. 10.5 is optimal for the skimmer I have, but 11 is within the operable height.
3. I would keep substrate out of the sump, just go with macro.
I do a 50/50 mix of crushed coral and sugar grain sand in the fuge area. It keeps it from compacting, and gives the bristle worms somewhere to hide, when I add them.
4. Think about dropping the water level in each chamber, and adding an underflow into your "fuge" chamber. Not following?
Nice design in general and I like your use of the graph paper to set it up. keep working on it!