Hammer coral death

Got my hammer coral in january. A couple of weeks ago i turned off the lights in my tank because of some algae problems i was having (caulerpa). When the lights came on after the three days it seemed like my hammer coral started to bleach a little bit, so i moved it down in the tank, but ever since then its been slowly dying. By now i pretty sure that its too far gone, but i would just like to know why it died. All my other corals are doing great. My params are fine. My salinity always swing a little, being that its a nano tank and im not great about top offs. I tried moving it too all different sports in my tank but noting helped. Could it be some kind of disease?

 

Need an image please.

Swings in nanos are huge problem. Make sure you are using at least one back up method to check your SG, and preferably a refractometer, and calibrate you refractometer as needed.