Anyone have a Dryice/co2 calculator

I remember a thread a long tme ago that had a calculator in which you could put the dimensions of your room in and it would tell you how many lbs of dry ice you need to get the room to certain ppm.

anyone remember? Or have the formula?

I recently used dry ice to cool my plants down and add Co2. I used about 5 pounds of dry to cool a room 10x10 or 1000sq feet and it got the ppm up to about 1600 ppm. so about .05 to.1 pounds per sq foot. Note that Co2 is a very inefficient way to add Co2 to a room due to its costs. It last only about a day before it disapears so that means you will have to get it every day. It also only lasts about 2 hours in a warm grow room so at 1.00 a pound if you were using it 24 hours a day it would cost about 60 bucks. If you were using it during flower only it would be 30 bucks. Multiple that by 365 it comes out to $21900 a year 243hrs a day and $10950 if using only in flower. That is a lot of money. The ice company would sure like you as there customer though.

Check out http://www.gardenscure.com/420/planting-indoors/124624-correct-co2-level.html for more info on dry ice Co2