dry ice

i saw a post about curing your herb with dry ice a little bit ago and got to wondering.
Dry ice produces CO2,
putting dry ice in a bucket of water in your grow room,
that would be good for your plants, right?

Unless you are getting lbs and lbs of free dry ice it melts too quick to be an economical option. You're cheaper off buying tanks or a generator, and those you can control the amount of CO2. There was a 3 day stretch a month or so ago it got abnormally hot, and I decided to try and use dry ice to cool my room off and supplement the air with CO2 so the plants could tolerate more heat. It's way too expensive to be a long term option. I don't remember the price per lb but 5lb blocks cost me about $20-$25. A 5lb block (broke in half, with each half on opposite sides of the room) would last about 2 hours. My room is 10x8x8 and temps were at 85. The dry ice positioned in the room and by the intake fan did drop temps 5-8 degrees though.