best way to control co2 from tank?

is there a cheap way to control co2 from a tank?

there are plenty of variables when it comes to how much co2 to have leaking from your tank for your harvest:

cubic footage
uptake by plants
how sealed the room is
etc

in our other room we have a Sentinal that automatically adjusts the co2 to around 1500pm on our burner. in the other room we want to seal, add a light, add co2.

question: im new to the tank method so please fill me in on how to set it up. i have the tanks (and will soon have a regulator, hose) but what is the best way to regulate the co2 tank? the CAP and Sentinal sniffers are great but expensive $$$. there is the timer by CAP (click here for amazon link) and the hydro store employee stated " just set this lil device to run for 30sec every 15mins while the lights are on and you're solid" i asked "so that will give me the desired level of co2 in my room without knowing the cubic footage?" he kept saying ya but i wasnt impressed.

seems as though most would say spend the money and get a digital sensor like sentinal or CAP. any cheaper way???

thanks

See link in sig for a good CO2 thread

cool man, just looked at your link. looks great....guess ill be buying another sentinal or one of those fuzzy logics. excellent resource thread!

I've been using a digigrow coco co2 controller for 2 years, it was 329.00 but I see them on ebay for 249.00 now.

I bought a CAP PPM4 about 3 harvests ago. I was initially nervous about it, as it seemed much too cheap (about US $200 at the local grow store). The store reassured me with a 3 year walk-in-walk-out-with-new-unit warranty.

So far it seems to be working fine. There is no ppm readout, but it seems to hold the setpoint fairly closely. Within 30 seconds of opening the flower room door I can usually hear the C02 tank solenoid click on. A 20 pound C02 tank lasts 18-20 days (10 x 10 x 9 foot room, overly full of 6 foot flowering plants).

Twice I've flooded the room with C02 attempting to kill mites. Each time I feared that I destroyed the C02 sensor, because it wouldn't come on the next day. Each time after one day it re-calibrated functional and was functional again.

I'll likely pick a more high-end C02 controller next time, but for now the price was right and it works.

http://www.hydrofarm.com/pb_detail.php?itemid=11711

dont waste your time using a timer. i have tried . its possible but you waste alot and never really know your co2 levels.

supermanlives said:

dont waste your time using a timer. i have tried . its possible but you waste alot and never really know your co2 levels.

Click to expand...

I agree, except to keep it off at night when using a controller. It was suggested to me to have the co2 turn on 1/2-1 hour after lights on and turn off 1/2-1 hour before lights out.

I think the point to be made is it no longer has to cost 800 bucks to get into co2. You can get a package on ebay with a regulator and controller for 300 bucks now. You can get a regulator for under 70 bucks now, add a timer and bottle and your on your way, add a 200-250 dollar controller down the road and your set.

My biggest expense was getting my sealed environment under control.

i agree controller is the way to go but if ya cant afford it yet. the regulator that ya have orderd should come with a sheet that with show ya what to set the regulator for desired ppm depending on the room size. i bought the one lazyman suggested and it works great.best of luck.

I know that CAP has this chart on their website. I think you need to download the reg-1 manual.

Still,

If you're willing to plod thru it, here's an article I kept in a Word.doc for a few years. It takes a lot of the guess work out of using a timer system if you can't afford a controller. It has worked for me in a sealed room, and my calculations proved out by how long the tank lasted. Of course you can't accurately calculate how much your plants will use. That's why a controller works best for maintaining the optimum. Good luck. -granger

CO2 Calculation

The air around us contains about .03-.04 percent CO2. The optimal level for a grow room is .12-.15 percent. When you chose to supplement your garden and increase the levels of CO2, you will do it on a schedule depending on the size of your space and various other environmental conditions. You'll need to have good ventilation to remove the stale air and the ventilation system should be on a timer to synchronize it with the CO2 distribution. To find out how much CO2 it will take to bring your grow room up to optimum levels you need to multiply the volume of the space by .0015. For example, in a 5' x 5' x 10' area, there is a total of 250 cubic feet of space. Multiplying that by .0015, you get .375 cubic feet of gas required to bring the levels up to optimum. You will then need to determine how long it will take to bring the space up to optimum at a given flow rate, and how often you want to replenish. CO2 tanks come with flow meters/regulators that emit 10-50 cubic feet of gas every hour. If you were to set your flow regulator at 10 cubic feet per hour, you would then need to divide the total amount of CO2 needed by 10 to discover how much time it would take to reach optimum. Using the example above, you would divide .375 (the amount of CO2 needed) by 10 (the flow rate), and get .0375 hours. Multiply that by 60 and you get 2.25 minutes. That is how long it would take to fill that room with the proper levels of CO2. You would then use a timer set to be on for 2.25 minutes every hour. This would bring the levels up to optimum once every hour and allow them to taper off in between bursts. The vent fan should also be on a timer that fires it up ten minutes or so before the next burst of CO2 to remove the stale, used air before replenishing. Maintaining these levels will increase the speed of your plants development, and its needs proportionally, so you must be prepared to keep all other environmental factors in balance with the plants increased requirements. This will mean watering and adding fertilizer more frequently, making sure there's enough light, and watching for signs of ripeness a little earlier in the flowering stage.

.12 lb. = 1 cu .ft.
20 lbs. tank = 172.8 cu. ft.

My room (600 cu. ft.) needs .7 cu. ft. to go up to 1500 ppm CO2 (from ambient of 350 ppm)

Release at Dawn, 3 hrs., 6 hrs., 9 hrs., during a 24 hr. (12/12) period
4 releases x .7 cu. ft. = 2.8 cu. ft. per 24 hr. period
Tank = 172.8 cu. ft./ 2.8 cu. ft. per day = 61 days supply from 20# tank
OR
.9 cu. ft. x 4=3.6 cu. ft. per day
172.8/3.6 = 48 days

.7=1150 (+350=1500)
.5=821 (+350=1171)

thanks granger2 but i have a controller now was talking about when i first started co2. i was posting that so he would know that the regulators normally come with a chart to set ppms to desired levels according to sq ft etc.