LoneStar hit it perfectly on the head. My main tank was in the living room and the sump was in the garage. I had my chiller located in the garage and it would short cycle (turn on/off constantly) due to the poor ventilation and heat buildup. Eventually caused the chiller to crash after a few months. I wish I would have tried his idea and framed in the sump to insulate it from the heat. Good info LoneStar!