So I found this journal and CD on my front porch one day...and lo and behold, it was a grow log. In that grow log, the person is using the same growtube and a 250 cfm in-line fan to cool the light. It seems pretty weak. It is set up very similar to Jamstigator's cab with one end open. I haven't read to the end of the log yet. Maybe he/she will switch that fan out for a centrifugal one. What do ya think? It seems that he/she is using the same type of fan to suck exhaust out of a 100 cubic ft area. Do you think thats enough? It says in the log that he/she thinks the fan is not very strong, because when he/she put a papertowel up to the "sucking" end of the fan, the motor started whirring like it was really straining. This is what makes me think its not a very strong fan. Should he/she change it? I'll post some of the pictures as soon as I go grab the CD that was left with the journal. Thanks