Ok, here goes, please go easy on me. I bought a 4" exhaust fan and a carbon filter to go along with it. I figured that I would use that combo to clean the air in my tent and extract the hot air as well from my CFLs. Now I think I made a mistake and while I could live with replacing the fan, I don't want to replace the filter, since it was $40. Question is, can I just get a higher CFM fan that's 6" instead of the 4" and just fab something up to reduce the diameter from the fan onto the filter? I guess I just got lured into buying a cheap fan on eBay and when I plugged it in, it did work fine enough, and even creates negative pressure in my small tent(100CFM fan, connected to the filter, reduces to 50CFM) but it's still more than enough since my tent is only about 20 cubic feet. I just wanna see if a bigger fan extracts more of the heat while still being able to use my smaller filter. Help, please! Sorry for the stupid(?) question.
You really shouldn't need a 6" fan for a CFL grow. I ran almost exactly the same setup with a 4" booster fan (~100CFM) and it worked fine. The trick is to have good airflow above the canopy using small clip fans, and put the exhaust at the top of the tent. Hot air travels upward. If you're really set on a 6" inline fan then you could just run a duct reducer (6" to 4") they sell them at home depot and most hydro shops. I would just try working with your setup for a bit first. You might find a fix without having to spend anything.
I have the carbon filter hooked up to the fan and it exits the tent at the top, like I've read about countless times. I guess what I need is a suggestion as to how I can bring in air from outside. I bought a little box fan that blows pretty hard for only having cost me $10 but I know that I need to use that in conjunction with something else. That's what I need to know and that's the help I need, especially considering that the ambient temperature is usually 84-87 degrees. If I could get something that equally exchanges the air, that would get my hopes up for actually doing the indoor grow. And I can't afford to run the a/c, especially considering that the humidity drops 40% in 15 minutes.