I did a lot of work on the ventilation of my grow tonight. I'm pulling cool air from an adjacent bedroom now and it's working like a dream. I didn't have a thermometer above the water until this week but I'm sure my temps were at 90F++ with lights on for this whole grow but now I'm sitting at less than 79F.
To do this I used 2 - 8" fans rated to ~800 cfm each. I have a speed controller for at least one fan so I have the exhaust slowed to hopefully around 400 cfm, which is the max limit of my carbon filter. So I assume there is about 700 cfm of cool air making into the garden and about 400 cfm being scrubbed. I read somewhere that it's great to have more intake than exhaust so this happened to work out.
Anyway all is looking good, technical information to follow. Super stoked on these...
As I type... lights on... 2x600w HPS
3 x White Widow Auto
Air temp: 76F
Humidity: 33%
TDS: 580
Res temp: 67F
pH: 5.9
~1.5 lpm per gallon
~500 cfm air flow
Pics:
It's easiest to see where it's been topped and super cropped if you look at the plant on the left.