Ok here it is. I have two seperate flowering rooms in the same room. One room is on during the day 12hrs then the other is on at night 12hrs. There is a lung room i guess you could say in between them with a/c, ballasts,timers flip/flop etc.. each room has 2 600watt cooltubes. Now what i want to do is cool all my lights with one stanely fan. Now before i go further remember my lights are on alternating schedules, im am not trying to cool 4 600watt cool tubes with one fan. Im trying to cool the two at a time that are on, and then when those go off i am looking for a way to make my fan switch to other rooms cooltubes since they will be turning on. I was hoping that somebody might know of something i can use. If i could build something i would get a y split duct and install a valve on the inside of it that would close up one end of the y duct on a timer thus openening the other end up. And hook it up directly to my fan. That would be awesome! is there anything like it? do you get what im sayin?