I think the title says it all. Are there any concerns using 65W power compact bulbs with a 55W PFO Ballast. The 65W are more readily available. Am I just not taking full advantage of the lighting capabilities, or is there a real concern with safety or the quality of the light emitted. On a side not, how high do you recommend MH be placed from the surface of the water? In this particular case, a 175W MH over a 29G tank. How tall of hood? I intend on cooling it with a 4" fan. Any general recommendations would be appreciated. I'm sure there is a recommended safe distance and then there is the realistic distance that people use in their tanks. This should maybe be a poll of how close is your MH and how tall is your hood?