400w set up fan timing help.

Hi rollers how are you all?!!

well basically this is quite a stupid question but i just cant seem to work it out....basically lately the weather has been great and my current temps in my tent are 37c at the peak of the day and im just worried its going to harm my girl shes week 5 into flower (psycosis cutting). i have a 4" exhause fan which runs 180mhr and a 4" inlet fan blowing air from opposite side of loft because cant get a fresh air supply from outside...so basically i have ordered a 4" rvk fan with a temp and speed control which at fastest pumps out 230mhr which is alot more than my current exhaust, so im trying to work out how to keep the fan on all day but then somehow tweak it too keep running on minimal at night to just pull out air from the tent..does this make sense to any one or have i had one too many doobies tonight .... cheers rollers!

Once you hit roughly 85+ Fahrenheit your growth will be reduced drastically, in both veg and flower. Try to keep your temps under 80 and you're good to go. If you can somehow swing it, get yourself a window a/c and set your intake duct up near it. Another, super ghetto (and on that note, well used by myself) method of getting some cool air into the tent is a huge bucket of ice sitting in a dark/cool corner of your room. Set your intake duct up to the top of it so it brings the cool air in. And of course, make sure whatever container your ice is in is big enough to hold it all when it melts haha.

As far as leaving it on at night, I don't really have any suggestions. What are your night temps like?

With good ventilation, veg temps in the mid 80s is actually pretty damn good. If you can keep it there, get the lights close and give it plenty of fresh air (or CO2) then it will respond well. It's a bit warm for flowering though.

100F is completely unacceptable during flowering though, unless you are growing outdoors.

I think the only way to controll the speed of the fan is to buy one of those thermostats you hook your ventilation equipment up to. I dont know of any ghetto way to rig a fan speed controller to change the speeds on its own. Good luck to ya.

if your fans got the temp and speed controller on it just set the temp nob to say 2 degrees higher than your lights off temps so once your lights go off and and the temps drop to say 70 degrees and youve set your fan to 72 then your fan will turn off unless it goes above 72! in which case it will turn back on for a couple of mins to get below 72! simple.

Easy breezy brother. Check this out:
http://hydrobuddy.co.uk/acatalog/In_Line_Fan_cw_Speed___Temp_Control.html

Kind