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Regulating CO2 Output - Solenoid and Timer


New Member
Hi everybody,

I'm aiming to rent out a 50# CO2 tank (20# tanks not available from my local welding supplier) to help my grow along - every bit of love and care helps! Right now I am searching for a solenoid CO2 tank regulator and a timer to regulate it.

I'm assuming 300 ppm normal CO2 levels and aiming for 1500 ppm peak, though I have read that 700 ppm is ideal for cannabis. (can anyone verify?)

The volume of my grow room is 500-560 cu. ft. (9'x7'x9' or 9'x7'x8' - I wasn't able to effectively measure the height but it's most likely 8-9 ft.) The room has no windows, only a door+fan for ventilation. Using HydroFarm's CO2 flow rate calculator I calculated ~10.2 cfh for 2 minutes / hr as being a flow-rate supported by most solenoid regulators.

Most importantly, are there any cheap outlet timers that you guys *know for certain* can be set to turn on for X minutes every hour? I feel like this is a reasonable feature, but I can't seem to verify whether any timers have it. (except for the really expensive $100+ microcontroller based ones)

Lastly, just want to double-check: what flow-rates are typically supported by solenoid regulators? I have seen ratings of 5-15 cfh to 8-30 cfh, but the cheaper regulators (like this $100 Milwaukee Solenoid CO2 Regulator) don't offer any information about their operating flow-rate. Any recommendations for solenoid regulators?

If I'm approaching this the wrong way or you know how to create a better setup, do tell! I'd love to listen :)

Thanks for reading!


New Member
look for a digital outlet timer they run about $20-30 at most.
What I have done in the past is I use the milk jug sugar water and yeast method.
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