Hooking up carbon filter to cooltube/ Budget ballast/cooling ?s

Oi, this is what I was hoping my setup could be. Is it efficient and is this the proper way to hook up a cool tube?

Basically I want to hook up the carbon filter to one end of the tube, duct, then have the fan on the outside. Here is a picture so you can hopefully clearly get the idea. Is this the way to go about it? I'm going to be running a 6'' inline fan/filter combo from GrowBright being purchased from HTG Supply. Also, this picture http://htgsupply.com/Files/Products/...ombo_Specs.jpg states that "each fan filter combo should be separated by a 6'' piece of ducting" Is this true? Does it have to be done? Obviously having to attach a bit of ducting would be troublesome if I was wanting to hook up the carbon filter directly to one side of the cool tube.


 
so basically I have a 400 dollar budget. I -might- be able to go up to 500.00 but that would push me back another month to get the rest of the things needed, digital hygrometer, an additional circulation fan,etc.

These are the two items im getting

http://www.htgsupply.com/Product-Lum...HPS-Grow-Light
http://www.htgsupply.com/Product-A-G...n-Filter-Combo

But this puts me at 512.00 w/shipping

Now I added the straight 6 cooltube to it adding 35.00. But using the standard reflector it comes with takes off that money. Would it be possible to only downgrade the 6 inch to a 4 inch inline fan but just use the reflector that comes with it saving me an additional  money without having to worry about heat? I obviously went with the cooltube for heat issues.

I have a window AC unit on 24/7. Brand new, and a 6400 btu. The closet runs at the same temperature as my room. I can keep my room 68-70 degrees during the summer no problem. I'd also have a 6,10,12'' fan or whatever blowing just on the bulb/reflector itself with another fan circulating air.

However I would eventually be switching to a tent (about 2-3 grows later) so I'm not sure if having a tent would actually affect the ambient temperature of the room and making it harder to keep cool.

Would I have heat issues with a 400 watt if I downgraded to a 4 inch inline fan and no cool tube?

As far as the ballast is concerned. I don't know what im looking for as far as brands go. The bad thing about greners and HTG supply is not only do they have "top sold items" but no review type system either..Basically I want to find a sweet spot between low and high quality, a little bit higher than middle of low/high quality.

So are there ballasts/grow light kits out there that isn't as expensive as a lumtatek but still good quality. I'm wanting to cover all my bases and research as much as I can before I put the order in.

 

Yea, The apollo was my first choice but after reading multiple forums it appears their bulbs are bad :S so needless to say the reviews on Amazon kinda turned me off from Apollo.