exhale 365 co2 bag worked wonders for yields esp in smaller spaces, cheap and lasts 9 months, never hurts to add it your grow room.
It adds humidity
Yea i dont notice it in my space but also have dehumidifier. And ill take the added co2 for the small amount of humidity it may emit
I agree with @Fever.
The amount of light it takes to justify adding co2 is a lot higher than most people think. If you’re providing that much light, it will probably take a few of those bags to make it happen. Then you need to be able to keep your space cool without displacing the co2 enriched atmosphere.
For most people, they’re either not needed or not doing the job they’re needed for.