homemade inline fan ??

Can you? Yes. Will it work? I'm guessing no. Inline fans are meant to put out high cfm under load, while that desk fan was meant to push mass volumes of air under no load. What I'm guessing will happen if you decide to do what you are suggesting is that your fan will not have enough torque to push the air through the scrubber.

 

nope that is not what you think it is. Inline Duct fans and booster fans and that fan are only to help move air through long runs of duct in use with a vain axial, or centerfugal fan. like this Amazon.com: Hydrofarm ACDF6 6" 400 CFM In-Line Fan: Home & Kitchen

to run air through a carbin filter you need a fan rated @ or above the CFM value of your carbon filter. Duct fans or booster fans will not draw enough air through a carbon filter to make any difference and will over time destroy the fan.

 

Everything said ^ is true.

Although that is a pretty small tent. You'd probably be able to get away with a 4" fan, although you might want to buy a 6" fan as you would be able to use a 6" fan to ventilate a larger space, if you ever had the notion to improve your grow.

 

I've found some awesome solutions to things like this in the DIY section here

There are more than a few threads in there that discuss odor control and/or ventilation. There's another one, this one, that explains different way to make your own activated carbon filter. I thought it had some pretty ingenious ideas in it.

 

is there any reason why you don't want to just buy an inline bathroom extractor fan? you can get them on eBay for about a fiver and require no modification because that's what they are designed for

there are better ones available obviously

 

This answers your question. Those bathroom extraction fans are meant to move air under no "load" (the carbon filter you're trying pushing through). Moving steamy air out of bathrooms is far easier then pushing air through a charcoal filter.

Mixted already answered your question, don't know why I'm posting.