Ten days ago, I purchased a favia frag. I drip acclimated it and placed it on the sand bed in the area with my other lps corals. After the first day or so, I started to noticed slow tissue recession. I've read that favias prefer moderate lighting and water flow. I have 4.8 watts per gallon, I don't really know if that's ''moderate'' or not, but the corals are doing well, except for this favia and one other zoa frag. I've tested and retested the water, everything is within normal parameters. What could be going on? Too much light for it?