I have a reef tank and I dropped my temperature slightly before getting my starfish. I noticed my tank temperatures varies between 74-79 F depending on how hot it is outside and what my A/C is at. I set my tank to 76-77 F which I know is not a lot of wiggle room. How much does yours fluctuate? And have you ever lost anything due to major fluctuations which happens in the ocean but stability is important?