I do not understand your question. Little fans inside for circulation you can get by with two. One needs to blow on the glass covering your light and in between the light and the plants to keep the air reasonble cool and the other just needs to blow around so it's windy in there, I usually put my second on at the bottom blowing up. Now if your talking about ventilation get yourself a 4" or 6" inline fan and run it through your light hood and then out of your tent and out of the room or house if possible, this will help tremendously with the heat buildup. does that help?
