Quote Originally Posted by cturner1984
hi the tent is 1.2 x 1.2 x 2
its a 4 inch extractor fan im not to sure what cfm means but the carbon filter is very big about the size 10 inches wide 22 inches long
thanks for the info on the ducting:thumbsup:im going to sort that out asap
CFM = Cubic Feet per Minute. It may be something different given that you use the metric system. The fan needs to move enough CFM to totally exchange the air in the room every 3 - 5 minutes. Every 5 minutes is fine. You need to calculate the volume of the room and divide by 5 (minutes) to get the CFM rating needed. At 20 - 30% to account for the length of the duct, bends, the filter, and any other drags on the fan. Get the fan size and then match it to a filter. Filters also have CFM ratings. Over estimate your filter needs by 15%. If you want to do the math properly you will find a useful link in my signature.

I'm asking b/c the filter looks a bit on the small size. It will likely work fine but with a shorter life. Similarly, over estimate the filter size and you get more life out of your filter (within reason).

Start those nutes at 1/4 strength and work your way up.

Good luck!