I just had similar experience, while on vacation out of town my house temperature dropped to 65F which caused my tank heater to run for longer times. This caused an over load and tripped the breaker, tank was with out power for about 12 hr and temp dropped to 69F. Zero water movement for same duration too, all fish and corals survived with zero impact. Big thanks to Brian (reefbox) rushed to my house at midnight to fix the issue.