RE: melted corals
The problem probably wasn't the temp in the house but rather the humidity. We had that drizzly weather on Friday and the humidity was probably close to 100%. When the humidity is high you have no evaporation. No evaporation = no cooling. Fans help break up the layer of heavy, saturated, humid air over the top of the tank and increase evaporation.
I would continue with your water changes, skim hard, and run carbon to help get over your current crisis. Even some clip on type fans from Walmart may help if you are in a bind. Without know how your tank is set up I can't really give you any ideas on what you need in the way of fans. It really depends on what kind of light you are running. Obviously, with MH you have more heat and more need more cooling. After having gone through a similar crisis I tripled the cooling capacity of my fans. I have extra fans I only run when I need more cooling. As a matter of fact I am putting in a heater to help keep it from getting too cool in the evenings.
Gary
125 SPS, 75 gal. LPS/softie reef, 9 gal. Nano