[greenbean36191]

If you've got experience showing that they do fine in low light and decline if moved to high light and you can find a few people that have seen the same thing then it might be worth doing some preliminary tests.

What I would do is set up two small, simple, identical tanks under one lighting fixture. I would tape something opaque on the walls so light doesn't spill from one tank to the other and then to control the light level I would put layers of window screen on the top of the tank. After a few months with both in low light, assuming no change in health, take a layer or two of screen off of one tank and see if you get the problem in that coral. If the results are what you predicted then I would repeat the experiment at least once more.

Make sure you log any info that may be relevant- parameters, changes in appearance, any differences between tanks, etc.

Obviously it's not an entirely convincing experiment but it's fairly cheap and easy and if you can repeat it with predictable results it's a start.

Only if that experiment turned out well would I even worry about the role of secondary infection.