If it's an in sump model, unplug the power and let sit for 20 min or so, then re-start.
If external, warm up about 16 oz of RODI water in microwave, very warm but not burning hot. Let your skimmer airline suck the water. You can do this with the in sump too when you fire back up.
Above is easier/faster than full cleaning, but you still need to do the full cleaning at least 1x a year. Better to follow Ray's every six months.
Killed my first coral in 1991, have tried to do better since. Always tricky.