I couldn't disagree more with it being "silly" to have a Sentinel in a 4x4 tent - it's a one-time $500 investment (the cost of a good light) that ensures a perfect growing environment, as well as a safeguard against things breaking, etc. - pays for itself with the first 1/8 of a decent harvest.If you had a 15x15 you were growin in then the sentinel would be a worthwhile investment. I didn't read back through the thread, but did this start with just wanting the Co2 controller? Are you looking at a Sentinel CHHC-1? My buddy has one of these and it works awesome. It doesn't claim to suck your dick when you turn it on like the one you are looking at, but wild claims are easy to make.
It does exactly what it says it does, you program the timers for the lights, you set all your environmental variables and it voila, it takes care of it for you. I believe it has the built in "Anti-Cook" that the sentinel light timers have so if something goes wrong and your "cooling device" stops working and the temp keeps rising it'll shut the lights off to get the room to cool back down.
THAT is the only reason I would purchase the Sentinel even. It hurts when 13 weeks of work goes down the toilet because a fuckin' fan died while you were away. Co2 is nice, but it's expensive and annoying to fill so I don't bother with it. The time it would take, the attention it would attract and the cost have always made me feel it would take to long to b worthwhile.
Again....15x15 sealed room, yeah I'm gonna run the sit. My 4x4 tent? A little silly.
My best investment thus far (without a doubt), and I've bought lots of stuff.