New ballast on M.H. light causes bleaching

[landshark]

So here's what happened. I changed out the ballast on a hamilton tech M.H. 250W fixture. I replaced it with an ice cap 250W electronic ballast. The next day I found my purple monti plate, and pink birdsnest had bleached. They were closest to the top. A neon green candy cane is also in trouble. Monti in the middle of the tank has been affected but did not bleach. All corals onthe bottom(mostly paly's) are not opening fully. Even the reddish algae I was having problems with near the top of my tank has turned grayish and appears to be dieing.(Won't miss this stuff). I am running a Giessman 13000K and was getting amazing growth till the ballast switch. Water parameters are within nomal although nitrate levels are slightlyhigher than the 0 the tank normally runs. Alk had dropped to 7 from 9, and calcium had dropped from 440ish to 400. Anyone ever have a problem like this after changing a ballast? I should note that the light seems a little whiter with the new ballast. Thanks .

[fencer]

I always thought electronic ballasts correctly "drives" bulb output. Maybe what you are seeing is the correct color for the bulbs. If the ballast is not working correctly...it might be overdriving the bulbs...

[KPG007]

Raise the lights for a week or so, then, over the course of a couple weeks, slowly lower it to your prefered hieght. that allows the corals to acclimate to the new light conditions.
As for the corals that are bleaching, as long as they are not dead, they will color back up (although this may take months depending on the severity of the bleaching).

Kelly

[Madreefer]

I just changed my bulbs and had a little bit of bleaching. After I noticed it I shut my lights off for a day and cut the mh schedule in half and have been slowly uping the time each day. Has'nt gotten any worse and the coral actually is starting to look better.