About 18 years ago I had a 30 gallon reef tank with a 400w monstrosity of a huge metal hallide bulb about 10 inches above the tank. We were all still learning a lot and I sure didn't know any better, so I bought a goniapora, an elegance, and a couple of softies. I forget if I had a clown in the tank. That tank stayed up for about 3+ years, until I moved and that goni was huge and wide open every day. I can't tell you why, but its a fair guess the nutrients were on the high side, the temprature was substantial, and the lighting was... well... a lot. If that helps answer any questions about what may keep them going, let me know... I would love to have another that big and happy.