Science Buddies: "Ask an Expert"

Hi,
for my science project i need to measure the ammount of CO2 is in a small air space. I am growing algae and the algae is removing Co2 from a small space and i would like to know an easy way to measure co2. i would appreciate if it didn't exceede $20-$40 hopfully with no shipping. Any advise is appreciated.
i recently found a project that used KOH as a way to see how much CO2 is in a bottle, and our projects are almost identical, so would that work?
The project is in grads 9-12 and the post was called measuring Co2 (if you cant find it the link is
http://sciencebuddies.com/science-fair- ... bf08e63b0e )
K-rock

Hi K-rock,

I read through the link you gave and since you are measuring the same thing, I think the KOH method is a good one to choose. The supplies for the KOH test should be less than $40. Did you have any specific questions about the method or supplies you need?