Newb grower requesting some guidance with ventilation and CO2 set up.

I have read a million posts and have gotten great information, but since every set up is different, and since I am getting to crunch time I decided to see if I can get some direct feedback.
I have a multi part question, and I am a complete novice grower but I have spent a little money and I am trying to do things right.
There are some specific questions in here, but I would also love some opinions and critiques of what I have set up if anyone is so inclined.
I have a 4.5 x 6.5 x 7 space (basically 29 sq ft and 200 cubic feet).
The two adjacent sides, the back wall and the left hand wall have a shelf about 16 inches from the ceiling that juts out about a foot. All the walls are covered with Orca except the ceiling and the walls above the shelf that do not seem to need it.
12 5 gal pots with two 5 gal reservoirs for drip/aero.
(2) 600 Watt MH for veg. Switching to HPS for flower and I got some
UVB reptile lamps, five of them for the last little bit. The babies will not even arrive for at least another 7-10 days so the reptile lights are a long ways off.
450 cfm inline exhaust fan. (HERE IS WHERE I AM QUESTIONING MYSELF AND THINKING ABOUT CHANGING THINGS)


Currently the exaust portion is totally sealed up. That is the carbon filter is mounted on brackets above the shelf back in the top left corner. 6" duct from there to the first hood, then the second, then back up to the shelf where there is a hole in the wall and the fan is sucking through all of this and blowing the hot, hopefully odorless air into the house. (Its odorless atm, we'll see once things get rolling.) I also have a 6" booster fan in a hole in the bottom left front corner of the room directly below the exhaust fan. I still have negative pressure but not so much as if the intake was passive, as I have read that you want negative pressure but not ear popping pressure.


I bought (maybe a mistake and lesson learned) a CAP AIR-3 thermostat/humidity/CO2 controller that is pretty cool but I am not sure I am going to need it.


Currently it seems that simply to keep the room at <80F the exhaust is constantly running. If the fans are constantly running, the CO2 never turns on, because the controller cuts it off to avoid having it sucked out of the room. I am wondering if I should just let the fans go 24/7 and have the CO2 on a timer. Will pulling air from the top left back corner of the room through a carbon filter suck the CO2 out before the plants can get it? Should I just release the CO2 at the floor and count on it making its way to the canopy as it heads up toward the filter?


I also wonder, and I am scared for the answer, if I should scrap the exhaust the way I have it, put the inline fan between the hoods, open them up and put the carbon filter outside the room having air pulled through the hoods, through a T section of duct and then out of the room via the inline fan to the filter outside. I guess if the vote goes for this set up I will be glad that I still have a week to 10 days to test this stuff before the babies arrive


Thanks in advance.

You have some time before the venting is required, germ under flouros or cfl's, place under 1x 600w Mh after 2 weeks or 6 inches high, then repot from 4 inch pot to 5 gallon, water well, and then link up the venting system to remoce excess heat, grow your system as your plants grow, avoid c02 so early in your learning, will just confuse things

Probably great advice, thank you. I should mention that I do also have an oscillating fan in the back corner and (4) 6" fans distributed under the shelves around the pots. I have been doing research for a year, have spent about 2k, put in countless hours getting the room built and outfitted, have been testing and adjusting things for over a week, have ordered 12 clones and upon arrival they are fully rooted and ready to be put in the 6" nets, so I am not sure I would pull back and just set the CO2 tank and regulator aside. I mean if I have it I might as well use it right? I am not going to hurt the plants with CO2 I know that. Also, I do have a nice (3) tube T8 48" fixture and some 65K bulbs that are good for 2400 lumens but those were going to be used for the clones I cut and mothers eventually. Also, I have an A/C unit that will cool the intake air, and I have turned it on. The room is now cooling to whatever temp I want and fast. I did not want to use the A/C in the winter, I am really kinda worried about the power consumption, and if I have to run A/C when its 35F what happens when its 95? Ugh. Really I am wondering about how and where to distribute the CO2 and how much. I am torn as to whether to tie it into the controller, or just set it at the appropriate cfm and put it on the timer with the lights at 18-6. I still have to do that math to figure how much CO2 I actually need, granted its not bein wasted out through my ventilation. Thanks again.

USE the CAP controller.....Plug the exhaust into it. Put the temp thermom dingus away from the wall at canopy level. Set your temps dial to twixt 80 and 86F on the controller. Set the humidity as you decide your plants will handle. Plug in the regulator. Set your gassing time to 1 min. (the amount you need for the cubic ft you have to raise the c02 level to about 11k to 12k ppm) and set the "off between gassing" time dial to how long it takes for the controller to come on exhaust the area.
Only run gas during flower!
You should now be good to go and it takes care of it's self.

Oh,,you have a fan going (of course),,put the gas tube into the back fan cage and it will distribute the gas nicely!

Ok more good advice. No C02 for veg? See I would have ran it from day one. I do not have any control over the gas through the controller. I think you meant that I should plug the reg into the controller, right? The controller has no dial for gas. Its a CAP-AIR-3. Maybe the better ones do, but this one simply has an optical sensor that turns the gas on when the lights are on, off when the lights are off. It also cuts the gas off when the exhaust is going. Now with the A/C going, I am able to keep the temp down much more effectively of course. I can let the controller turn the CO2 on and off IF I run the A/C all the time. My meter was spinning like a top before the A/C... so I REALLY would rather not have to run it. It sounds like you have experience with these controllers. It seems to me either its a bit off, or I am confused about how it is supposed to work. To maintain 77-79F I have to set it at 72. I have been shooting for 75-78, should I let it go to 80-86 like you said? Even with no gas during growth stage?? I know many points here are just preference, I am simply looking for as many opinions as possible so I can decide what is going to work best for me. Thanks!

OK,, just looked up your unit....And you've got the unit made for C02 generators!!!! You need one of these (following links) to do what I said to above. TRUST me on this subject, you WANT one of these controllers as it just makes things EASY and you won't "waste" C02! It IS worth the investment...
For what yours cost,,,,the jump to the Autopilot is very affordable! Take the CAP back and upgrade!
I might suggest these....
http://4hydroponics.com/autopilot-digital-environmental-controller NICE PRICE!
This will do everything you need and you will save $ on the AC cost as this unit will shut it off and on as need to YOUR settings on the controller!
OR
http://4hydroponics.com/cap-co2-2e-temperature-humidity-co2-controller
I've had these for years and they work great for me - pricy maybe for you?

Oh,,,yeah that's right ,, NO gas in veg.....What you get from doing that,,,,isn't worth the cost of doing it......Flowering only.