Receding prism coral growth patterns

[zeno9]

I've had a similar issue in my tank since switching to LEDs, what kind of lighting are you using? I noticed with my LEDs, if the colony is at an angle, the light doesn't wrap around the piece like it would with other lighting systems, and that's caused some of my pieces to recede due to lack of light.

I found that by placing the colonies flat, facing the LEDs, the recession stopped and growth started again. Not sure if this is the issue with your tank, but I've had about 5 colonies that had similar problems.

[fluxable]

Finally got around to testing the water. I'll try to get a picture up later when I can clean the camera lens.

My tank's been stable for six months now, with low bio load. It's a 120-gallon tank, with two clowns, a yellow watchman, and a few corals. The favia was the first coral I added, about three months ago. I also added a montipora spongodes around the same time, which has been growing well. The favia initially grew over the sides of the frag and even started growing onto the rock, but now it's turning white on the edges, with some skeleton showing. There are a lot of pods crawling around that area, including some long, skinny ones.

My setup includes a Lumintek pro 240 light and a reef octopus 150 skimmer in a 30-gallon sump. Here are my current parameters: Salinity 1.025, Nitrate 0, Calcium 420, Alk 7.2 dKh (I've been using kalk), and Mg 1280 (I just added some to try and raise it by 100ppm). The favia recently divided its mouths, and I haven't seen any feeder tentacles at night for a few days.

[fluxable]

Here's the rewritten post:

Second photo is a month old, shows some growth before decline.

[fluxable]

I'm still stumped on why my reverse prism favia's receding around the edges. I've dipped it, moved it to a new location with lower light and flow, but the recession's still happening. The coral's had a slight algae growth on it since the beginning, which isn't found anywhere else in the tank. I've had other favias in the tank for the same amount of time with no issues. Any ideas on what could be causing this?

[fluxable]

Still looking for some insight into my receding favia issue.