Hi cfm needed for 25 cubic foot room? buying a 4inch inline filter to push 135cfm is that overkill? http://www.ebay.com.au/itm/140896774032?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1438.l2649 for http://cgi.ebay.com.au/ws/eBayISAPI.dll?V
dont sound over kill at all but remember 15-20% air movement is lost whenyou attach piping and co2 filter
You want the air to be exchanged at least 5 times. 25cubic feet X 5 = 125cfm Carbon Filter ~ 15% loss = 18cfm So now you are looking at 107 CFM To be on the safe side, in case you want to upgrade to acool tube or you need more ducting in the future, or if you need to control fan speed in case you have to be more stealthy, i would go with the following: 25cf x 5 = 125cfm + (lets just say roughly 50 lost due to fan controller and carbon filter) = 175cfm. I have a 2x2x5(20cubic feet) and i'm able to control my temps with a 4inch cool tube and filter attached AND a fan speed controller set at the lowest speed. my fan is rated 190-95 cfm. Dont skimp out on ventilation man.
amazon.com http://www.amazon.com/Fan-Filter-Combo-Inline-Hydroponic/dp/B00AHF1WNW/ref=sr_1_36?ie=UTF8&qid=1370456963&sr=8-36&keywords=4inch+inline+filter Cheaper and more CFM.