| Probably adjusting to the lights. They are a lower light coral, just give him a few weeks to acclimate.
When you added the halides, did you acclimate your tank to the new lighting?
I acclimate every time I get new MH bulbs just because of the jump in intensity is VERY extreme and stressful for the corals. In my case I lift my light fixture about 6 inches and lower it over the course of 2 or 3 weeks.
Other people use window screen between the bulbs and water to lower the intensity until the corals adjust.
I would NOT recomend moving it up. They prefer being on the substrate. Also make sure that it isn't being covered up by substrate at all. |