A few months ago I purchased a 1" diameter yellow plate coral and put him on the sand bed. For the first few weeks or so he looked fine, but then he started not puffing up much (looked more like colored bone than fleshy coral). I went away for 2 weeks and left the fish auto feeder dropping some pellets every 3 days. After I came back I can see some bone extending from the center where his mouth is and it looks like he may be slowly dying. (previously my stylophora tipped over and my acan stung and it died 2 weeks later, so I don't know if there may be toxins in the water. I just hung a media bag of carbon in the tank just in case) Any idea what caused this? Not enough feeding? Too much light, too little light? I have had an algae problem for many months but am running GFO in a reactor and my phosphates are measuring zero, nitrates undetectable. My Ph has always been low. Between 7.8 and 8.0. Have had a hard time controlling alk (I let my alk/calc dosing run dry for 1 to 2 weeks and alk was 7.0 when I checked it. (I have since brought it back up to 10. usually it seems to be about 7.8 or so. I have a hard time maintaining it, probably due to the algae.) Any suggestions on what I can try? Thanks.