Any thoughts on Co2 in the grobo?
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There is alot of good info posted here on Co2
Personally I say save your $$$ with co2 and Grobo…
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Thank you
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I personally added CO2 this time around (second successful grow in Grobo). I had a 20lb tank from previous brewing days, hooked up a regulator on a timer, ran the hose into the door. I will likely permanently modify an access hole in the rear/top of the unit after this harvest so my door closes nicely again.
CO2 makes a difference! 
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Thanks for the input.
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Hard part with Grobo and co2 is it’s exhausting your Co2 out of the box all the time… So how do you maintain 1200 to 1500 ppm with the light off?..
How are you controlling how much to dose?
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Did you grow the same strain?
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I’m running (I don’t have the exact dosage as I’m about 2400 miles from my Grobo at the moment) a very very small flow. It cycles on for 4 minutes and rests for 30 min. It does not run at “night”. I don’t yet have a ppm meter, but a single plant will only take so much.
My commercial grow is laying the CO2 anywhere between 1800-3200ppm.
The Grobo leaks (obviously), but the addition of even some extra CO2 is quickly noticeable with the plant.
Start small. You can always add more…
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In a topic like this you’re always going to have mixed opinions. Hey if it’s works and your happy I’m all for it. 
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How long does you tank last? I’m going to do this procedure at some point. What was your average ppm?
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Never gauged the ppm, but the above cycle has lasted 2 full grows. It’s a 20lb tank.
Edit: The only other factors(variables) different would be the seed. Last great grow (STILL smoking that stuff) was an LAOG Kush. This one is Jelly Rancher.
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Thank you 
What kind of timer do you use? So the regulator is open if you plug it in and closed when it’s not plugged in? Can I use a household multi wall timer and monitor that way and make adjustments accordingly in the timer?