i have one 250watt in my 40 tall (30") and its looks fine..
there is alittle bit of darkness (still bright) on the ends, but gives me a spot to put my lesser light corals
yes i have 2 fans right now and keep my window open some.. i have the 250watt and 150 actinic vho.. i like the combo.. slight yellow tint but nothing ugly
spring time im going to get a chiller for it...