How do you save money keeping tank at 74*?(and, as opposed to what temp?) I assume less heater operation but what is your ambient temperature? What region are you located? I'm in swfl, 78*ambient temp right now. What's your strategy?I started keeping my reef at 74. Save me 60 bucks a month and no noticeable difference.
Fan on a light timer can keep things cool - you don't even have to get fancy with a temperature controller.
Have you double checked your temperature probe/controller with something with mercury in it, or the like? Hard to imagine that 71 degree room has an overheating tank.