First Active Ventilation Set-Up-----Great results. Need input on possible additions.

After reading this forum for six months(and a book called "Ed Rosenthal's Marijuana Grower's Handbook) I decided to try my hand at an indoor grow. As we all know, picking the proper equipment to buy and implement is possibly the most crucial aspect of any grow(certainly an indoor operation). I used the knowledge of this group when it came to picking lights(a T5 eight bulb 2ft long for veg/600 dual spectrum HID for flower). Nutes and other odds and ends seemed to be a matter of choosing which brand name you liked best(as long as it met the requirements of the plants and ph).

The one issue that no one seemed to give me specific directions on was ventilation. Don't get me wrong--there was a plethora of info about CFM and humidity---but no one said this brand name or this combo will get the job done. So, I thought that we would list what we are using, what we payed for it, and the strengths/weaknesses of said products. This would have been a huge help to myself as a new(er) grower going from outdoor to indoor worrying about heat/humidity and the DREADED ODOR for the first time. So, without further preamble:
My grow room is a walk in closet that had an existing AC vent(huge plus). The dimensions are: 6' x 5' x 8'
I decided to go the fairly inexpensive route. I purchased the following combo from an online supplier:

6" Fan/Blower--400 cfm
6" Carbon Filter w/flanges(52mm carbon layer--18"long 8" diameter--weight about 9lbs)
25' of 6" silver duct work(the standard foil bendable kind--same as most of us use on our dryer exhaust)
(2) clamps to secure the vent to the filter and the fan--same as we use on our dryer--has the screw to tighten or loosen
price shipped: right under $150

bought a few odds and ends at a Home Depot such as 90 degree elbows, Y splitter, thin metal straps that I use to hang the duct from the ceiling, and a reducer to change a 6" down to a 4". Cost: $20

The last item I got would be optional for you:
Active Air Fan Speed Controller: 24 bux from my local grow store.

I have a passive intake that is disguised as an AC vent and I also did the same with my exhaust. It was not possible to exhaust outside my home and I always worry about malfunction and exhausting smelly air with my neighbors being less than 50' from my house. The system works great. Humidity is steady at 35-40% and temps during the day are never above 80 deg F. That is great because my outside temps for 6 months a year are above 95 and humidity is never below 80%. There is no smell at the exhaust point. I also ran an extra duct from my central AC unit to my grow so when the AC runs my room gets 2x the air and one of these vents runs directly into my HID. The other AC vent runs down to 6" above the floor right in the middle of my room so the cool air gets a chance to stay in the room without being exhausted.

Pls list what your setup is and the costs associated with it.