Do not vent with co2, run closed loop. Or vent at night only.
Shroom bags are only garbage because they're made by scammers. No placebo behind science, mycelium produces co2 and consumes some o2 or it dies. The actual mushroom frutbody consumes alot of 02 as well as producing c02. If levels of c02 get above 650ppm mushroom growth is retarded and becomes abnormal. So shroom rooms must be vented and alot to keep the co2 levels below 650ppm or they will skyrocket into the 1000s ppm within a couple hours. I'm a professional mycologist, who ran a gourmet mushroom farm for 7 years and it does work, you have to make your own and have basic knowledge of mushroom cultivation to have it work best. Put 20 bags in a 4×8 tent and tell me that won't boost growth. Each block only costs $1 or 2 dollars to make (hence scammers.) I ran my hydroponic microgreens operation along side my shiitake grow and circulated the air between grow rooms; the growth rates of both plant and mushrooms improved