Sure!
Well, first of all it looked very nice. Usually installations in hotels and restaurants look very dismal, but this looked like a real reef tank..something I would like in my house. It was light with metal halides, although I am not sure of wattage(restaurant employees don't like you peering into the hood when people are eating

). The rockwork was very well aquascaped, with 2 overflows hidden by healthy dense growths of halimedia. Among the fish I noticed were banghais, clowns, a pseudochromis, a few tangs...That's all I can think of. Corals included various
soft corals, an anemone, and even a tridacnid clam I believe. All of it looked very healthy, including the fish. The dense growth of halimedia told me the tank was doing well. That is why I am suprised that the fish are croaking. One thing I noticed was the MH would go off in sections, with one bulb at a time. When I showed up for dinner, only 2 were on. When I left, only one appeared to be on still. I'm guessing they have around 3 bulbs and they turn them off in a sequence(sort of a slow dusk effect). I wonder about the photoperiod. Fish need a decent amount of dark time, so I hope they do not have the lights on too long to prevent the fish from getting rest. However, judging from the installation, I doubt that this is an issue. No idea about filtration. The tank is behind the hostess counter, and like I said, they would have gotten rather annoyed if I went peeking under the stand. Believe me, I really wanted to.
I'm sorry to hear that the tank is having problems. Hopefully, the problem will get figured out. I'd be happy to show up and do some testing and brainstorming myself. Usually, an experienced eye can deduce possible causes. Especially if there are a couple of sushi snacks sitting around.

Just kidding. Anyways, good luck with the tank.