The 2,400 gallon tank is constructed of painted 3/4" CDX plywood with 2 inches of  Styrofoam insulation all around.  The exterior support (truss) is cherry wood landscape timber.  The 1/2" x 84" x 28" plate glass window opening is supported by 4" x 4" fir timbers. 

The aquarium has 5 heaters totaling 1,900 watts.  The heat cycles on 3-4 hours every 24 hours when the outside temperature is 40 degrees.  At 32 degrees with the wind blowing the heat is on every 12 hours.  The estimated insulation "R" factor is about 20 or above.  When the outside temperature is above 50 degrees the heaters to not cycle on.  The pumps, lighting and 40 watt UV supply enough heat to maintain the 78 degree set point.