Questions on Zoanthids?? I`m perplexed!

I have a 55 gallon mixed reef in its infancy. Livestock include three ocellaris clowns (yes, I know too many, I'll be rid of one here soon), a firefish, a yellowtail damsel, and a hippo tang. For corals, I have green birdsnest, orange digi, GSP, eagle eye and dragon eye zoas, purple pocillopora, a duncan, green monti cap, and orange monti cap. My problem is that my zoas don't seem to want to open as much as they used to when I first got them. My lighting seems to be fine enough because all my SPS are doing great. They always have their polyps open and they're encrusting on my liferock beautifully. They're also growing like weeds. My zoas, however, seem to have receeded and don't like to stay open. I dose two little fishes C-Balance daily and perform weekly water changes. I have an mp10 and two hydor koralias for water flow. For lighting, I only have a dual bulb t-5 that's supplemented with two Kessil a150 14,000K LED pendants. The zoas seemed to like it better with just the t-5s because when I added the Kessils, they looked awesome and fluorsed great, but wouldn't stay open much. Like I said, all the SPS is going great, though. I wonder if I have my calcium too high for them or if the LEDs bug them. Lastly, I've noticed little fluorescent green nudibranchs on them. Any takers as to what's going on?

 

Yeah, the zoas in question have bright green borders with red centers.... I did a little further digging and it looks like I have zoa eating nudibranchs. But I wouldn't put it past the lighting as well. Thanks everyone! Now, any tips as to how I eradicate nudibranchs??