Yea well again I've read it a million places before but i think you have to keep the temp around 70's-80's you dont want it get get much hotter then that my plant is in a controlled temp apartment that never gets below 71 degrees for the plants sake. My cfl's are only a few inches from the plant tops because cfl's dont really produce heat I also had the 23w or 100w cfls. They never really put off any heat for me to the point where the plants can actually touch the light and nothing happens so I dont know what to say about that. I'm not an expert in anway so I really hope I can help as much as possible. You shouldn't really need it for two 23w cfls but do you have a small fan for the heat? It'll provide some circulation and heat reliefe for your plants..

p.s. 150 watt halogen is not a 150w cfl. Halogens do get very hot cfls dont. When you goto the store or look online to buy it, it would be a 42w cfl.. that equals 150w:thumbsup: