My 12g nanocube always stayed at about 78 degrees with the lid on. I mounted the lid over the tank yesterday and the temp this morning was 74. Our house AC is set at 73 so my guess is the tank will probably settle there. Right now I have a clownfish, some cuc and a few LPS. Should I consider a heater? I plan on sticking with LPS and softies. The lid used to protect the tank from drastic temp changes, which sometimes but rarely happen in south Florida. What's everyone's thoughts about an ideal temp to maintain? I know stability is more important than an actual number but I'm just curious.