unfucking real,,take the co2 and shove it out the fucking door,,percentages,amounts,all kinds of effects my ass,,,it is a waist of money and ideas(mind fucks yourself),,if you have the lighting,,thats all you need and a little air vent to prevent mold,,,,,,it is just another way to take your money for a grow that you can produce better if you no how,,,,,,,,,,,,,,,,show me pics of c02,,,not a problem,,except for the money,,if runs out,,and no money,,now who is going to buy it...,,,,,,,,,,,,,,,,,,,,,,,,,,,worry your head over nothing at all,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,Jack