In search of a fan

Grow box dimensions are 4x2x5
Total cubic feet: 40

Grow Light: Grow Ace Elite HPS+MH Air Cool Tube Reflector Digital Dimming Ballast Grow Light Kit
Carbon Filter: 4" Mountain Air Carbon Filter - 180 CFM

I am still looking for an inline fan, but Im not sure how much CFM my fan should have. Is the fan suppose to have the exact same CFM as the filter? Is the filter less efficient if the fan has more CFM than the filter?
My filter is 180 CFM (So it would recycle all of my grow box air 4.5 times per minute.)
Here is the filter I am planning on buying: http://www.ebay.com/itm/230962095069

The filter needs to be rated at a higher cfm than your fan, othewise the air passes through the filter too fast and doesn't get scrubbed. A 4" inline fan will be good. You can also use a speed controller to dial in the perfect airflow.

This is the fan I use.http://www.ebay.com/itm/4-INCH-INLINE-FAN-HYDROPONICS-EXHAUST-DUCT-VENT-BLOWER-190CFM-F001-/280897495567?pt=LH_DefaultDomain_0&hash=item4166cba20f#ht_4249wt_945

^^^good advice^^^

Ok I will get a fan controller along with the fan you suggested.

Since my set up is only 40 cubic feet, couldnt I still go with the 180 CFM filter and use it with your 190 CFM fan, but run the fan on medium? This way it won't max out the filter and still cycle my air at least 3 times per minute. Or am I better off getting a different filter?

190 is close enough. It won't overrun your filter.

Yes, as long the filter has a higher rated cfm than what your pulling, it will work. You could get a smaller filter as well. I don't know if Mountain Air makes a smaller one, but I use the 4x8 size which is the smallest Phresh makes. It's rated at 150 cfm and with my setup, I'm only pulling about 50 cfm or less at the filter. I have the exact same size tent as you, so our setups will prabably be pretty similiar.

My speed controller is set in the medium range.

Also, my fan is outside my tent connected with about 4' of insulated flex duct(noise reduction). If your fan is placed in the tent or hooked outside right up to the exaust port, you may be able to run your fan even lower than mine.

Nice, how do you know how many CFM's you're pulling? Did you just set your fan controller to 1/3 power? Im interested in your set up now, haha. Im going for 4 plants at the moment and going to LST them for a bit then scrog them to keep them away from the light. Also since they are different strains, I have no idea when each will finish so I was thinking of also setting up some chicken wire and dividing them horizontally as well. Im doing this so they don't tangled and I can still pull out each individual plant.

What is your set up like? Do you have a thread or journal? Curious to see it

No, I haven't bothered doing a journal on here. Currently I'm doing an 8 plant semi sog grow. I vegged them for about 3 weeks, but thier uncut which I call it semi sog. Here's a couple a rcent picks.

I'm just guessing at the cfms. I know they have meters hvac guys use, but I don't have one.

Oh yeah, thier Northern Lights from Royal Queen

Ok so is there any real need to have a net and do scrog? I was just going to use it to keep it away from the lights on top of the LTS Im going to do to it. I want to make sure I can have 4 plants (maybe more if you think my carbon filter and grow space can handle it) and get access to each individual one. The reason for this is that I dont know when each strain will finish when, there are 6 different kinds, 8 total plants.

If you want to scrog that's fine, but you'll have the room to do pretty much any kind of grow you want. I keep my light about 8-10" above the canopy, but it could get closer. You can put your hand on the cooltube and it's just warm, not hot. A good carbon filter will be able to handle as many plants as you can stuff in there. How many plants you grow at once depends on how long you veg. them for. The longer the veg. time, the bigger they'll get and the more room they'll need. As you can see, I only vegged them for about 3 weeks and my tent is quite full. It's going to get a little fuller over the next week or 2 as the bloom stretch finishes. If your going to veg. longer than that, 4 plants would be max. 3 plants vegging for a while with some topping or lst would be the best fit in my opinion. Is there a reason your set on 4 or more?

Only because I have clones of 7 different strains and I would like to do as many as possible. The way its laid out in the box now with 4 plants looks nice and seems to fit too. Ill try to upload a picture of the design soon. The clones are all the same age but Im worried that some will finish earlier than others and will get tangled up with other plants in the scrog. What about using vertical dividers between the plants?

Not sure what you mean by vertical dividers, but I don't think any sort of divider is nessacary though. Marijuana isn't like a vine that weaves and tangles. Individual plants can be pulled out without a hastle. As crowded as my tent looks, the plants are not tangled at all and infact I pull them out to water and rotate them.