I am no way telling everyone to lower there tank temperatures. 77-78 is perfectly fine. I personally have not noticed any issues with going down to 74-75. It is also beneficial for me as we ship many corals across the nation and heat is a bigger killer then cold. By shipping at an already slightly lower temperature in the summer months does work to my advantage for the health of the coral. You could say I would have the opposite issue in the winter, but I find keeping a coral warm is much easier then keeping it cold.