Mates, with co2 we are looking for a 'sealed room' during lights on. That means ac is a must!!! We run between 1400-1800ppm for 12 hours straight, NO VENTING during lights on. We can run as high as 90 degrees during early veg and then start bringing it down to about 78 while at the same time reducing humidity toward the middle of the flowering period in order to encourage the plant to seal itself. The higher temps are required in order for the plant to metabolize at a higher rate, which it needs to do in order to use the co2 effectively. Feeding & watering have to be adjusted for the higher uptake of the plant. Basically I would not mess with co2 unless a near perfect environment can be provided. Otherwise we are just wasting our co2

Good luck mate!

Unity

__________________
600w scrog Aurora Indica
http://www.rollitup.org/indoor-growi...t-gassing.html
Got never ending mg/n problems? Growing in a tent? Let's talk!

Well soon I was planning on buying a vented shade for my 400w MH/HPS my In and Out vents were going to be connected to the shade. Wouldn't Co2 be benificial in a room where it was hard to maintain a constant 75-80°. My closet likes to stay in the 84-86° range atm. I have a fan blowing over the top of the seedlings and my In vent I made a ghetto scoop, the air (which this time of year is nice and cool) blows towards the light so the temp by the little seedlings isn't too bad.

__________________
<insert cool sig here>

Once you seal the room without ac your temps will go up beyond 100+ degrees. You can try to minimize your exhaust and that way you may be able to maintain around 1500ppm constant but you will go through a 20 pound tank once a week. My mate does it this way, he has his exhaust fan on a fan speed controller and can therefore regulate his exhaust cfm. Not efficient though, since in my swealed room one 20 pound tank lasts me about 3-4 weeks maintaining a constant 1500-1800ppm. So, in dollars this means, he spends $80 a month in co2 and I spend $20-$30 a month. You can pay for ac real quick with the savings

Unity

__________________
600w scrog Aurora Indica
http://www.rollitup.org/indoor-growi...t-gassing.html
Got never ending mg/n problems? Growing in a tent? Let's talk!

I thought adding a vented shade/cool tube helps cool the room down?

__________________
<insert cool sig here>

Adding a vented hood will only reduce the radient heat from the light, the overal temp in the room will go up in a sealed environment. It sucks I know, I tried soooooooo hard to build a sealed room with no ac. Well, I admit defeat
You will not regret the ac mate, I use a window unit ($249) which has the condenser portion in the garage.

Unity

Attached Images

	1120IMGP3592.jpg (58.9 KB, 5 views)
	IMGP3559.jpg (49.8 KB, 6 views)
	IMGP3379.jpg (64.2 KB, 6 views)
	IMGP3376.jpg (72.3 KB, 6 views)

__________________
600w scrog Aurora Indica
http://www.rollitup.org/indoor-growi...t-gassing.html
Got never ending mg/n problems? Growing in a tent? Let's talk!

unity, how many plants are you harvesting with that setup what is your total cf of your grow area? and do you think that not exchanging the air at all is benifecial to your grow? what happens to the spent air the plants have used if you dont exchange the air at all? do you grow donkey dicks with that or are your buds about even with your mates that does exchange the air? dont give me the strain variable either, I want to know if your buds end up bigger than your mates because of how you use the co2. im not being a dick either just curious as you seem to know a lil about co2 setups at least.

__________________
http://www.rollitup.org/grow-journal...g-stadium.html
All statements and photos are part of a fictional story concocted for entertainment purposes only.

Hi Offgrid, I don't mind you asking Q's mate
You know I do not like the idea of not exchanging the air at all even though many in the 'know' say it's cool. I personally feel that the plants must transpire toxins etc. These toxins could build up over 12 hours and possibly harm the plants. I have an IQ Air purifier (3 stage Hepa filtration & carbon filtration) that I run during lights on. My last grow (first grow with co2) was a complete disaster. I was never able to completely figure out what was wrong either. Back then I did not have an air purifier in there and the air was always very heavy when I opened up. Now it smells completely clean, no odors what so ever. I have to admit though that I was also dialing my 'drain to waste' set up along with experimenting with using tab water along with hard water nutes. So bottom line is , that I never found out exactly what went wrong.
This time I have no hick ups to date, I'm doing a scrog (pics)
My mate is running a 400 watt and I'm a 600, so I do not have an apples to apples comparison, but I think as long as you can maintain the elevated co2 levels (doesn't matter how) you will realize the benefits of co2. The trick is maintaining it in a cost effective way. His problem is going to be high heat, which will give him not as tight nugs, but the co2 will go a long way in tightening them up.
I started a thread in Hydro, you are more then welcome to follow along, we may both learn something since it is my first attempt with this set up and Scrog.
Help with flipping my first sgrog :)
The idea with co2 is to improve the quality not necessarily the yield, at least that's how it was explained to me. You know those super tight nugs you get at the dispensaries, that's what I'm looking for

"do you think that not exchanging the air at all is beneficial to your grow?"
It is beneficial to my grow in the sense that I do not have to interrupt my plants 'steroid' trip during lights on. It takes a while for the plants to speed up their metabolism from the co2, so if I can avoid taking them of the juice every 2 hours for venting then I will.

"what happens to the spent air the plants have used if you dont exchange the air at all?"
The plants do not use air (oxygen), they use the co2, tha'ts why I have to supply it in a sealed environment.

Unity

Attached Images

	IMGP3556.jpg (106.5 KB, 5 views)
	IMGP3560.jpg (102.7 KB, 4 views)
	1118.jpg (101.0 KB, 2 views)
	1119IMGP3586.jpg (93.4 KB, 2 views)
	1120IMGP3593.jpg (110.5 KB, 3 views)
	1121IMGP3594.jpg (137.2 KB, 4 views)
	1121IMGP3597.jpg (106.1 KB, 5 views)

__________________
600w scrog Aurora Indica
http://www.rollitup.org/indoor-growi...t-gassing.html
Got never ending mg/n problems? Growing in a tent? Let's talk!