Dry ice

I'm considering using dry ice in my next harvest to try and increase my yield. My question is how much should I use? I grow in a 4x4x7 tent and have around 10-15 girls in there. Any answer will be appreciated. Thanks

At 2-3 bucks a lb save your money for a tank. And you have to have everything perfect for co2 to even work. Dry ice is gone in 24 hours so you need a steady supply.