[Reeffantic]

I just wanted some opinions and maybe some lighting help. I recently setup a new lighting system for my tank which includes 2-250 watt 10K Usio MH's and 2-110 watt actinic VHO's over a 4' tank. They yellow corals seem to be getting lighter. Instead of being yellow they are white with a yellow tinge. In fact, just about all my acros seem to be getting lighter. The wild colonys seem to be coloring up nicely. In fact, one brown acro is turning purple.

Any thought as to what is happening? You do not think they are bleaching do you? How would one determin the difference between a shift in color and a general bleaching episode?

[Reefland]

How long have you been using this new lighting on your tank? What type of acclimation did you go through? It could be that the light is a bit more than the corals can handle right now which is why they are turning pale. You could try to lower the corals that are turning pale on you or maybe even reduce your photoperiod a tad bit.

The difference between a color shift and bleaching event in my opinion is the bleaching is going to happen fairly quickly and once it starts, it is very hard to stop. The coral will turn complete white and eventually loose all tissue. I think this would be an obvious event if you were experiencing it.

Tell us a bit more about your new lights and when you got them.

Regards,

[Reeffantic]

The lights are relatively new, about a couple weeks but there are a couple other things to consider. One, one of the corals is new and originally came from ... shoot what is his name. I am tired and cannot think...large wholesaler out of California. Now I remember, Walt Smith. The other was rescued by a friend who took a green Poccilapora originally housed under PC's and put it under old 6500k MH's. It turned a beautiful yellow, like it was supposed to be in the first place. I would think the Walt Smith coral would be acclimated to bright light.

The MH light system, like I said is new. They were under 396 watt of PC's before so your thoughts about the light being to intense are worth considering. Maybe I will lower them. Its funny though, the other corals seem fine. When I started with the MH's, it was a week of 4 hour days, the next 5, and now 6. Is that to fast of a progression? What are your thoughts?

[Reefland]

I think your acclimation process is more than adequate however these corals may still be adjusting to the change in intesity. It surely wouldn;t hurt to move them a bit lower in the tank and see if they respond any differently.

[kevinpo]

It sounds like they are OK to me. Corals can continue to shift colors and lighten or darken for 6-8 months. They shift colors slightly as your bulbs age and again when you replace them with new ones. Remember some corals even SPS do not like too high light intensity. You need to know which ones will and will not tolerate very high light conditions. Some will stop or grow very slowly when placed in too high of light environment.

HTH,
Kevin