The window has a due western exposure and gets its most direct sun in the afternoon for a few hours, but there are no trees/shade out there and I think styrofoam is a great idea. Because I will adjust my photoperiod to occur when I am home in the evening, the tank lights will be on anyway during the afternoon hours of direct sunlight. Also, the window already has cheap, white plastic horizontal blinds on it so the light is muted, not direct. I am thinking to start I will set the lights for 11 am-9 pm, as I go to sleep around 10-10:30. Although the hood holds 2x96 watt bulbs, I am going to start with one bulb and no CO2. 96 watts on a 50 gal seems enough when taking into consideration the add'l window rays and if I need more light I can always add another bulb (96W or something lower, dunno). As for the temp of the water, I keep my air conditioning thermostat set very low (70-72 degrees, we are in FL)... probably set the tank at around 76-78. Won't the tank heater just kick off if the water starts to warm?
29G planted, low tech: Anubias, Crypt. spiralis, Java fern, Java moss, Christmas moss, floating Ceratotopsis
6 platys, 6 black skirt tetras, 10 neons, 6 glo-light tetras
50G high tech, a tank of rescues: 12' pleco, clown loach, striped raphaelle catfish