Well I'm now a week in since adding co2 to my grow, and the tank is already empty.. I have a 20lb tank in a 10x5 sealed room. I have the ppm4 controller and it kicks on at 1450 and turns off at 1500. It seemed to me it was kicking on once or twice an hour for about 10-15 seconds. This is in veg so 18/6, the co2 is on 18 hours. I actually added the tank in the room on monday, and it ran out this morning, on sunday. 18*6=108 hours it lasted. So in flower it would have lasted 9 days. Hauling around these tanks sucks lol. How long do ya'll get out of your tanks?
I get about 2 weeks, but mine only comes on every 45 min. I also only use Co2 in Veg. I think you are realizing how expensive it can get.$$$$
I dont have that problem and I am at 24 hrs of lights 4x4 room. Dont have PPM gage but I do have it come on once every hour for 15 mins and my flow gage at 5 I use the activeair 20 regulator and 20 lbs of CO2 I been running for two weeks now and dont have to fill yet. For a total of 6 hrs a day so I donno whats up maybe I need a PPM gage cause my ppm can be really low compaired to you with a Acurate setup using PPM