Just a few questions about co2 for you more experienced users:

1. Where can you get your tanks filled? I was thinking paintball shops and welding shops where else should I look?

2. I realize it's none of their business why I need it, but what are good excuses for needing to fill up to 3 20lb tanks? I was thinking paintball, kegorator, any other good ones?

3. ABOUT how long does a 20lb tank last in a closed off room with ventilation at about 1250ppm?

4. Where are good places to get your tanks? I've heard you basically exchange your tanks for their prefilled ones, so there's not much use spending money on nicer tanks.

5. What kinda equipment will I need for my room? I'm looking to get a Sentinel CHHC-1 controller and probe combo for my controller. Do I just need a regulator and a tank and I'm ready to go? I already have exhaust fan and dehumidifier. Any other parts I might need?

Assuming a 20lb tank could last a week, I'd ideally like to be able to get 4 tanks and only have to fill 2x every grow. I'd also like strict monitoring of environmental control as well as a co2 system that can maintain a steady ppm of about 1250, while also monitoring my temperature turning on my exhaust accordingly.

Any help would be greatly appreciated.

Thanks!

Just a few questions about co2 for you more experienced users:

1. Where can you get your tanks filled? I was thinking paintball shops and welding shops where else should I look?

Places like soda vendors or some hydro shops


2. I realize it's none of their business why I need it, but what are good excuses for needing to fill up to 3 20lb tanks? I was thinking paintball, kegorator, any other good ones?

your dad is a welder and youre getting them for him? they most likely wont ask. you brew your own beer too right?


3. ABOUT how long does a 20lb tank last in a closed off room with ventilation at about 1250ppm?

how bigs the room? i have a 4x3x7 and i keep it at nearly 1500 during daytime and my tank has lasted over a month and a half. theres some calculations you can run to figure this out

4. Where are good places to get your tanks? I've heard you basically exchange your tanks for their prefilled ones, so there's not much use spending money on nicer tanks.

go to ebay, i got a 20lb for 100 brand new with free shipping. cant beat that. i also got the solenoid valve for 130 or so brand new too

5. What kinda equipment will I need for my room? I'm looking to get a Sentinel CHHC-1 controller and probe combo for my controller. Do I just need a regulator and a tank and I'm ready to go? I already have exhaust fan and dehumidifier. Any other parts I might need?

timer, solenoid valve. thats all i run

Assuming a 20lb tank could last a week, I'd ideally like to be able to get 4 tanks and only have to fill 2x every grow. I'd also like strict monitoring of environmental control as well as a co2 system that can maintain a steady ppm of about 1250, while also monitoring my temperature turning on my exhaust accordingly.

im too high to understand this last one hahaha and check out my grow and see the results. (Big fat buds)

On the last question something I once set up that was totally unrelated might be useful there. Microcenter (and I'm sure various other electronics parts and service places) sell these little digital units you attach to fans that only activate between certain temperature ranges you can set. I suppose rigging one to the exhaust fan power could solve that issue for you.

Thanks for the feedback!

My room is about 10x10x8, what kind of calculations could I use to find out how long a tank would last me? I figured there would be too many variables between my heat, plants consumption, exhaust times etc.

I currently have a temperature sensor timer thing that I use for my exhaust. I have it set to 80* as I'm currently not using co2, and it works very nicely.

Are there any other creative places to get your tanks filled? I've asked my hydro shop and he doesn't do that, and what exactly do you mean by soda vendors? Like the guys who drive the trucks to refill local stores?

That last sentence wasn't so much a question as a statement of how I would like to deal with getting refills. I'd like to get a few tanks, enough for a complete grow and simply fill them up once before each grow so not to draw attention to myself getting refills all the time.

Thanks!

As for the calculations, conveniently, you have the same cubic foot grow room as their example. Since youre running a 800 cubic foot space youll need 1/3 (.333) cubic foot of co2 to maintain 1500 ppm then you divide that up into your flow amount by 2 and so youd need to run it at 0.2 cubic foot for 15 minutes every half hour.

easy enough right?

but thats all going to depend on how many times you exhaust too.

For co2 refills just look it up in your yellow pages. and the beverage places are those ones. welding shop would probably be easiest to find and they dont charge too much. just say you weld and tell em its for you tig or mig welder or something.

hope this helps

For Temp, Humidity and Exhaust control I use the Control Wizard.

Attached Images

Control Center & Carbon Filter.jpg (50.6 KB, 8 views)

On your calculations, you're saying to take .333 of my 800ft, or 266.4 and then divide by 2? I'm a little lost as to why you're doing the conversions you are and how you came to dertermin the final answer? Do you have a link to some page that better explains things?

I'm still a bit unsure of the beverage places, or what to look for in the yellow pages.

That setup looks really nice, but I'm a sucker for the conveniences of digital and have heard nothing but good things about the Sentinel CHHC-1 unit.

Thanks!

In my research I stumbled upon this page which seems to be a great guide to co2. They give a formula to determining the amount of co2 i'll need to keep my room at 1500 ppm.

"To calculate the amount of Carbon Dioxide needed to enrich a room to 1500 ppm, first calculate the volume of the growing space. For instance, an 8×8 foot room with an 8 foot ceiling would contain 512 cubic feet of space. Determine the CO2 needed to enrich to 1500 ppm by multiplying the volume of space by .0015.

512 x .0015 = 0.768

Thus, 0.768 cubic feet (or rounded up to 0.8 cu ft ) of carbon dioxide will be needed to enrich this room at 1500 ppm. 1 lb of CO2 is equal to about 8.5 cubic feet at normal temperature and atmospheric pressure."


Is the assumption that there is 8.5 cubic feet of co2 in 1 lb of co2 correct?

So if my room is 10x10x8 I would have 800 cubic feet x .0015 to get 1.2 cubic feet of co2 to reach 1500ppm in my room?

This leads me to my next question about ventilation.

What type of ventilation is needed for a sealed room? I'd like to make the 20lb co2 tank last as long as possible keeping my room at 1500ppm.