14,000K MH burning corals

[IndyReefMan]

For the past year, I have been running (2) 150w 20,000K MH DE Coralvue on my 72 gal bow reef. I supplement that with 130W 10,000K PC and 130W actinic and use them to create a dusk-to-dawn effect. The MH photoperiod is 10hrs/day. I decided to switch to (2) 150W 14,000K MH DE Phoenix to gain a little more PAR. I acclimated the 14,000K bulbs carefully with screens for a period of 4 weeks. Everything went fine. However, now that the screens have been removed, I can't keep the 14,000K phoenix bulbs on for any longer than about 3hrs/day without burning my corals. The LPS corals are all near the bottom of the tank and I have various species of Acropora, Montipora, and Pocillopora near the top. The MH bulbs are about 8 inches off of the water surface (that is as high as I can get them) which means that the closest corals are within about 15-16 inches from the lights (7 inches below the surface). The Montipora and a few of the Acropora suffer the most. When the lights are on for any longer than about 3-4 hrs/day, they start burning the tops facing the lights. What the heck is going on? How can 150W bulbs be burning Acro? Any suggestions? Am I doing something wrong? Any help or recommendatios will be greatly appreciated.

 

[TANGBOY5000]

By burning do you mean they turn white at the tips? If yes, then that means growth.

 

[IndyReefMan]

No. The tops of the coral branches are burning. For example-- a horizontel branch of Acro will be burning along the entire surface that is facing the lights. Polyps aren't coming out and it is turning white along the surface facing the lights. The bottoms of the branches (away from the lights) are just fine.

 

[chadfarmer]

suggest putting a screen back on or moving the corals to the bottom of the tank

 

[Ti]

soounds like bleaching, they need to b acclimated to the new lighting,