I feel for you, I've had 2 naso's before this one, they just didn't eat. Ive had this one about 1 1/2 yrs now. You really need an established tank with LR for them to graze on.
Is he a new fish ? Does he just have it in the morning ? If hes new it might go away. I had that when I first got my PBT it went away it was stress from ajusting to tank.
If you want to spend some $ aerofoamer or euroreef is the way to go. personally I have 2 seaclone 150s on my 125 tank people say there junk but mine work just fine
I agree damsel problem. Naso should be ok in there for a while, but will have to get larger tank. I would try to get damsel out when tank has been dark for a while. I had the same problem, my naso is doing great now.:)
I had that happen to one of my corals when I poured the water in to fast from a 5g bucket. the water landed right on it. took a few weeks to get better. Now I allways slowly syphen water in & out of tanks.
The biggest one I have is an orange sponge it's doing great ,had it a couplle of years now. The only thing I can say is everything in my tank does well from what I believe is good lighting & regular water changes:)