One of my tanks which is a 120Gal, live rock only, no sand, with only soft corals, a 15" sized prized Ritteri, a Powder Brown, Orange Shoulder, Sailfin, Anthias, and a Six Line Wrasse. 1200Gph return, 22x flow. Everything was running well and happy with a Metal Halide 250W DE 15K bulb, and the bulb was almost 1.5 years old so I decided to change it. I bought a new 10K bulb, however when I went to change it, the ballast died
So I had to order a new one.
On the 4th day I started to use the refugium light to light the tank, but of course that is way to small and not bright enough, but the fish looked happier and the Ritteri opened about 75%.
By the time I got the new ballast the lights were off for 7 days. Yikes! I immediately set it up and turned it on. I immediately noticed the odd metal halide burn in smell. The fish freaked out and all went into hiding, and the Ritteri shrank and pushed out it's mouth. After about 4 hours the fish came out and appeared OK and ate OK, but the Ritteri looked about the same. It was night so the light went off with the timer. About 2 hours after the light went off, I noticed all the fish were in the corners of the tank, when normally they would go into their respective sleeping spots, just chalked it up to odd behavior.
The next day I decided to put a filter on the top of the tank, reducing the light to about 65%. The coal still remain all closed, but look to be molting, something I always see them do when growing. The Ritteri put his mouth back in, but is still 50% open/shriveled, and ALL the fish appeared to have white on their fins and were breathing really fast
I thought they were just stressing because of the new light, even though it was already reduced. By lunch time, things hadn't improved. So I did a full water check, all parameters were all GOOD. I suspected perhaps it was a chemical or something else that wasn't measurable so I added a 1 pound bag of activated carbon. By night time and lights out, the Ritteri looked better, still shriveled, but tentacles were 75% full. Some coals have some polyps starting to push out. But the fish looked about the same, still white, barely moved much around the tank, only a couple ate that day.
The next day, today, day 2 or 48 hours with the new lights, lights are off right now because the timer doesn't go on until 9:30AM. I wake up and the Salfin is dead, bristle worms were having a feast, removed that. Ritteri, 50% looks ok, but the other 50% has a stringy slime tangled in the tentacles, can't see too clearly. Will update this post when lights are on....
So what exactly is going on with this tank!?! In my 15+ years of reefing I have never seen such, can this ALL be the result of the light change!?! Going from light, to darkness, to REALLY bright? I've never had this kind of reaction. Did the 7 days without light cause a die off of the coral? But I've gone with 3-4 days with no lights, with no issues. I've moved tanks from San Francisco to Seattle, a 4 day dismantle, and had nothing unusual occur. I'm puzzled and feel like I'm treading new ground, things don't look good right now. Extremely sad my prized Ritteri is perhaps dying
Curious what other experts out there have to say....?

On the 4th day I started to use the refugium light to light the tank, but of course that is way to small and not bright enough, but the fish looked happier and the Ritteri opened about 75%.
By the time I got the new ballast the lights were off for 7 days. Yikes! I immediately set it up and turned it on. I immediately noticed the odd metal halide burn in smell. The fish freaked out and all went into hiding, and the Ritteri shrank and pushed out it's mouth. After about 4 hours the fish came out and appeared OK and ate OK, but the Ritteri looked about the same. It was night so the light went off with the timer. About 2 hours after the light went off, I noticed all the fish were in the corners of the tank, when normally they would go into their respective sleeping spots, just chalked it up to odd behavior.
The next day I decided to put a filter on the top of the tank, reducing the light to about 65%. The coal still remain all closed, but look to be molting, something I always see them do when growing. The Ritteri put his mouth back in, but is still 50% open/shriveled, and ALL the fish appeared to have white on their fins and were breathing really fast

The next day, today, day 2 or 48 hours with the new lights, lights are off right now because the timer doesn't go on until 9:30AM. I wake up and the Salfin is dead, bristle worms were having a feast, removed that. Ritteri, 50% looks ok, but the other 50% has a stringy slime tangled in the tentacles, can't see too clearly. Will update this post when lights are on....
So what exactly is going on with this tank!?! In my 15+ years of reefing I have never seen such, can this ALL be the result of the light change!?! Going from light, to darkness, to REALLY bright? I've never had this kind of reaction. Did the 7 days without light cause a die off of the coral? But I've gone with 3-4 days with no lights, with no issues. I've moved tanks from San Francisco to Seattle, a 4 day dismantle, and had nothing unusual occur. I'm puzzled and feel like I'm treading new ground, things don't look good right now. Extremely sad my prized Ritteri is perhaps dying

Curious what other experts out there have to say....?