Green Star Polyp Problems.

SO, I have had my green star polyp for around 2 months now and he was thriving, out of all mt corals was the only one to start spreading, I have had my tanks running with just hermits and corals for about 3 months, last weekend i went on a small weekend trip but i had a family friend come turn on and off my lights for the two days i was gone. that Sunday i decided i wanted to have the tank params checked and possible add a few fish and some snails, ad the glass was building up some allege. that day all water parameters were perfect but it had been a while since i changed the water since i only had corals and crabs, i was doing only the monthly 25% change, so i got 2 clowns and 2 Mexican turbos, and a heater, i set the heater up at 75 degrees and floated the bags, while they were acclimating i did the water change, then finished with the addition of the fish and snails, but my GSP was closed i figured it was because of all the disturbing activity, the next day he opened up a little but its been a full week since he has opened at all and in worried that something is wrong. I turned the temp down as the tank is normally running at about 77 with the heater set to 75 i set it so it stays at about 76.5 knowing that corals can like colder settings but i don't want to lose the snails. i also turkey basted him to get the sand on him off, as i have and issue with sand getting kicked up by a secondary pump that refuses to stick or stay put even when wedged on in rocks. Help Did i kill one of the hardiest corals around or is it just being moody. He is in a top location with excellent light and medium water flow,

i have a 29 gal bio cube all water params are in the green and fish, snails and other corals doing great