I have a box that is 4'L 2'W 6'H I was thinking about getting a 400W HPS to use with the florescent lights I already have. My question is what type of heat it puts off. I live in a very hot part of the country and my box is in a barn that is not climate controlled. For example it's supposed to be in the 80's tomorrow. In the middle of summer we get 100+. I have grown outside very successfully despite the heat. So what do yall think should I go with the 400 or get a 250?