A helpful thread for me, My tent is 4'x4'x6.5' and I'm using COBs. With no circulation and 400W of COBs, the temp never goes over 82 degrees. I keep the doors closed except when feeding/watering. I've got one of the solenoid regulator/valves for a CO2 tank, this model:
http://www.ebay.com/itm/Hydroponics-Extoic-Injection-System-Regulator-Grow-Room-Flow-Meter-Control-CO2-/331550956367?hash=item4d31fa1b4f:g:MScAAOSwrklVUWTg It works perfectly, I couldn't ask for a better regulator.
What I'm not sure is, seeing as I'm not venting my tent, most of the CO2 will stay inside except for what leaks through the zipper and out the closed up vent holes in the bottom. How often would I likely need to have CO2 come in via a timer and what setting? Using the calculator at the beginning of the thread it says for my tent and at .5 CFM, it says to leave it on for 13.9 minutes.
What I'm needing to know is how many times a day I would need to have it come on for those 13.9 minutes? If I leave it on for the 12 hours solid, that would run the tank out in about 700 hours. I could leave it on 12 hours solid for a month at that rate but I'm guessing that would be a waste of CO2, so how often a day, while the light is on, would I need to have a timer turn the CO2 flow back on for those 14 minutes? I'm guessing maybe 5-6 times but that's a total guess.
Thanks!