Who Gives A Fish Forums

I'm pretty sure I'm on the right track here, but I thought I'd run this by you all. I just added a new Acan lord to my 29g tank, and it's sitting on the sandbed under an Aquamana COB LED that's about 18" off the water. My current settings are 15% white and 30% blue. I've been using an eggcrate cover from Home Depot, which I know reflects a lot of light.

Today, I took the eggcrate top off for a bit during feeding, and I noticed the color in the normally purple area of the acan had shifted to a brownish hue. I put the top back on, and a couple of hours later, the acan was back to normal.

So, here's what I'm thinking:

1. The eggcrate top must have been reducing and dispersing the intensity of the LED's, and when I removed it, the lighting changed, which didn't agree with the acan.

And

2. Indirect lighting might be the way to go. I've got a spot in mind just south of a frogspawn, at the base of the rock, which seems to get most of its light reflected back from the sand and the nearby corals.

Does this sound reasonable to you all?

IME, I've never seen color shifts occur that quickly. In my experience, browning is usually a sign the coral's not getting enough light. I've always had better luck with my corals when they're in direct light.

Another possibility is excessive zooxanthellae within the coral, which can be linked to high nutrient levels.