Jega I wonder if a big factor in yours is the shrimp blowing into the corals. Right now I slowly feed pellets to the fish and they eat about 100% of them. I have a good CUC, I guess they just eat fish poop. I also have a healthy population of pods and mysis, but I don't really add food to the water column that just blows around for the corals to eat...
My tank is pretty low tech also, I really wanted to try emphasize biological filtration. So now I have no mechanical filtration at all, no skimmer, no sponges, filters, nothing, and the water is crystal clear, nitrate and phosphate at 0ppm, and sandbed is clean. I have live sponges all over and worms and all kinds of little bugs that live in the sand and rocks.
I think when I feed I will start blasting some finely mashed pellet dust into the water so the corals can eat it, or as suggested earlier that gonipower and I am going to look at phytoplankton.