I am currently growing it I was a big fan of critical+ so I have given her a go she was topped at I would say 8week an is a beautiful bush wat u do is find a local dry ice dealer boil some water an give feeding a like that. It's called poor mans growing will show her off a lit later she is in my gallery will have updates on her soon but same thang just cheaper an time consuming but it does work an after water has cooled water UR plants with it an watch them praise u
I started in a cold month, January. I only have one furnace and so I got a inline booster fan and duct. Pulled air from above the furnace over to the grow room. Based on the results of the 2nd grow I'd say it really helps. So much, I got a 2nd fan and duct and I'm not pumping CO2 into both grows. Even the 2nd grow is kicking up since the addition of the CO2.
I don't have a closed room so I just pump it in using a 250 CFM fan. I don't know how much CO2 is actually getting in there, I just base things on plant growth and how happy they look.
If I had to pay a few hundred for a CO2 system and completely seal the room, I don't know if I would, I don't know if you could do the same thing my just keeping the plants in veg longer or just adding more plants.
I only did mine because it was dirt cheap, however, I do have to run the furnace on warmer days, so I run the A/C on days I might not have before.