[dennysnook]

Is a seperate fan running constantly when lighting is turned on typical in a Cool Tube type application for a 3x2x6 cabinet? I have seen a few setups that have the fan/filter inline with the cool tube all in one line. I would assume that the fan would only run when temperature is high, but it just seems that it would trigger the fans at a constant rate to keep temps down. I am trying to keep costs to a minimum, so one fan would be preferred, but I need some insight into how much the exhaust would engage. Reason being: I want to use co2 so I don't want constant exhuast which would defeat the purpose. Does this mean I need two fans, one for exhaust through the cool tube and one for cab exhaust? Or can I eliminate the cool tube and just let the exhaust vent the heat out with a regular hood. I want a 250-400 hps and temps no more than 85. Can someone please stear me in the right direction.

Thanks in advance for any help.