Used one the first time I ever grew. I have no idea if it worked or not, but according to all the "top guys" the word is; No. They don't work.
I would love to have a CO2 meter so I could see how much the bucket raises it. I'm one of the guys that thinks "if you add more co2 in ANY amount, then something added is better than nothing added"... but then the 'big guys' all say "if you can't hit 1200-1500 ppms and lock it in, and cycle with fan and blah blah blah" that you are absolutely throwing your money away.
I don't get it.. I think if you add any CO2 it helps.. *shrug*
With that said, I'm not using buckets anymore as I think they are a bit of a waste of money. I'd rather get a tank and regulator.. throw it on a timer, and "waste my money" that way... because I think that would actually be worth it.
....anddddd I rambled. :rofl: